Read about Professor Shari Forbes' research in this Masters of detection article.
Shari Forbes is a Professor and former ARC Future Fellow in the Centre for Forensic Science at the University of Technology Sydney. She is also the Director of the Australian Facility for Taphonomic Experimental Research (AFTER), the only facility in Australia that allows scientists to study the decomposition of human cadavers. She completed a Bachelor of Science (Honours) in Applied Chemistry and Forensic Science and a PhD (Forensic Chemistry) at the University of Technology Sydney. She was the founding Director of the Forensic Science program at the University of Ontario Institute of Technology (UOIT) from 2005-2011 where she also held a Canada Research Chair in Decomposition Chemistry.
Shari’s research investigates the chemical processes that occur in soft tissue decomposition. Her research aims to increase the knowledge base relating to decomposition chemistry to identify an accurate biochemical signature for estimating time since death. She has studied the chemical processes of decomposition in terrestrial, aquatic, and atmospheric environments throughout Australia, Canada and the USA. Shari’s fellowship research focused on identifying an accurate chemical profile of decomposition odour using advanced analytical instrumentation. The research has assisted police canine units to enhance their training methods for cadaver-detection dogs and blood-detection dogs deployed to forensic and mass disaster investigations.
Shari collaborates with the NSW Police Force, Australian Federal Police, and Fire and Rescue NSW. Shari’s research has been funded by the Australian Research Council, United States Agency for International Development, Canada Research Chair Program, Natural Sciences and Engineering Research Council of Canada, Canada Foundation for Innovation, Ontario Ministry of Research and Innovation, and the Canadian Police Research Centre. She was recently recognised among the top 50 most influential women in analytical sciences in the world, being named in Analytical Scientist’s 2016 Power List. Her contributions to forensic science have been recognized by several awards, including the Wildlife Crime Tech Challenge, UTS Alumni Award for Excellence, Ontario Ministry of Research and Innovation Early Researcher Award, and the UOIT Junior Research Excellence Award.
Shari is a Fellow of the Royal Society of New South Wales, an invited member of the Australian Academy of Forensic Sciences and a member of the Australian and New Zealand Forensic Science Society (ANZFSS). She is the Pacific Officer for the Initiative on Forensic Geology, a directive of the International Union of Geological Sciences. She is regularly consulted on forensic casework and assists police to search for and locate human remains using police dogs and geophysical equipment.
- Shari is a member of the Self-Assessment Team progressing the UTS application for an Athena SWAN Bronze award, as part of the Science in Australia Gender Equity (SAGE) pilot. UTS is one of 40 higher education and research institutions in Australia joining this national gender equity pilot program for women and men in STEMM fields.
- Fellow of the Royal Society of New South Wales
- Invited Member of the Australian Academy of Forensic Sciences
- Member and Vice-President (NSW Branch) of the Australian and New Zealand Forensic Science Society
- Member of the Canadian Society of Forensic Science
- Officer for the Pacific Region, International Union of Geological Sciences, Initiative on Forensic Geology
Can supervise: YES
Volatile Organic Compounds
Two-Dimensional Gas Chromatography
Investigation of Human Remains
Introduction to Forensic Taphonomy
Skeletal remains were retrieved from a cave in an arid desert environment. The submitted material consisted of dried grass, soil, and malodorous skeletal remains wrapped in leather. After examination, it was revealed that the smell had not been due to recent decomposition but to adipocere. The cause of death was listed as "undetermined" and a suggested date of death as "unknown." Although adipocere usually requires a damp environment or submersion in water to develop, this case provides further evidence for the rare possibility of adipocere formation in an otherwise very dry environment. Wrapping of the body in leather material had produced an impermeable barrier which had sequestrated and preserved bodily fluids allowing anaerobic decay with fat hydrolysis and adipocere formation. Microenvironments may have potentially significant and quite idiosyncratic effects on decompositional processes which may initially confuse investigations.
Collins, M, Gel, M, Lennard, C, Spikmans, V, Forbes, S & Anderson, A 2020, 'Application of a microfluidic gas-to-liquid interface for extraction of target amphetamines and precursors from air samples', Micromachines, vol. 11, no. 3.View/Download from: Publisher's site
© 2020 by the authors. The investigation of clandestine laboratories poses serious hazards for first responders, emergency services, investigators and the surrounding public due to the risk of exposure to volatile organic compounds (VOCs) used in the manufacture of illicit substances. A novel gas sampling interface using open microfluidic channels that enables the extraction of VOCs out of the gas phase and into a liquid, where it can be analysed by conventional detection systems, has recently been developed. This paper investigates the efficiency and effectiveness of such a gas-to-liquid (GTL) extraction system for the extraction of amphetamine-type substances (ATS) and their precursors from the vapour phase. The GTL interface was evaluated across a range of different ATS and their precursors (methamphetamine, dimethylamphetamine, N-formylmethamphetamine, benzaldehyde, phenyl-2-propanone, ephedrine and pseudoephedrine) at concentrations ranging between 10 and 32 mg m-3. These gas samples were produced by a gas generation system directly in Tedlar® bags and gas canisters for controlled volume sampling. When using gas sampled from Tedlar® bags, four of the seven compounds were able to be extracted by the GTL interface, with the majority of the VOCs having extraction yields between 0.005% and 4.5%, in line with the results from an initial study. When samples were taken from gas canisters, only benzaldehyde was able to be detected, with extraction efficiencies between 0.2% and 0.4%. A custom-built mount for the GTL interface helped to automate the extraction process, with the aim of increasing extraction efficiency or reducing variability. However, the extraction efficiency did not improve when using this accessory, but the procedure did become more efficient. The results from the study indicated that the GTL interface could be employed for the collection of gaseous ATS and incorporated into mobile detection systems for onsite collection and analysis of volatile com...
Varlet, V, Joye, C, Forbes, SL & Grabherr, S 2020, 'Revolution in death sciences: body farms and taphonomics blooming. A review investigating the advantages, ethical and legal aspects in a Swiss context', International Journal of Legal Medicine, vol. 134, no. 5, pp. 1875-1895.View/Download from: Publisher's site
© 2020, Springer-Verlag GmbH Germany, part of Springer Nature. Taphonomy is the study of decaying organisms over time and their process of fossilization. Taphonomy, originally a branch of palaeontology and anthropology, was developed to understand the ecology of a decomposition site, how site ecology changes upon the introduction of plant or animal remains and, in turn, how site ecology affects the decomposition of these materials. In recent years, these goals were incorporated by forensic science to understand the decomposition of human cadavers, to provide a basis on which to estimate postmortem and/or postburial interval, to assist in the determination of cause and circumstances of death, and to aid in the location of clandestine graves. These goals are achieved through the study of the factors that influence cadaver decomposition (e.g. temperature, moisture, insect activity). These studies have also provided insight into the belowground ecology of cadaver breakdown and allowed to develop useful protocols for mass disaster managements in humanitarian medicine. From the results obtained, new scientific disciplines have arisen, gathered under the word "taphonomics" such as the study of microorganisms living below/on a cadaver (thanatogeomicrobiology), and join the more classical forensic sciences such as anthropology, botany or entomology. Taking into account the specificities of the study object (human cadaver), primordial requirements are needed in terms of security (physical and environmental) as well as ethical and legal concerns which are studied in the Swiss context. The present review aims to present in a first part the concept of human forensic taphonomy facilities (HFTF, also colloquially named "body farm") leading to an enrichment of forensic sciences with new "taphonomics". The second part is focused on the mandatory points that must be addressed for a HFTF approach, especially because it requires a specific place to undertake this research which must...
Iqbal, MA, Ueland, M & Forbes, SL 2020, 'Recent advances in the estimation of post-mortem interval in forensic taphonomy', Australian Journal of Forensic Sciences, vol. 52, pp. 107-123.View/Download from: Publisher's site
One of the key elements in a criminal death investigation is the estimation of time since death, as this information can assist with identifying the victim and prosecuting an offender. Estimating post-mortem interval (PMI) is a challenging task given the many variables that act on the rate and process of decomposition. This review presents current advances in estimating PMI in forensic taphonomy. The use of scoring systems based on visual observations and the development of empirical formulas have been proposed for soft tissue analysis. In the absence of soft tissue, the citrate content of bone and radiometric dating are recommended for PMI estimations of hard tissue. Recent studies have shown an increased focus on associated evidence found on or near the remains. This includes botanical and mycological evidence such as vegetation changes, the presence or absence of certain plant species, and fungal succession. Decomposition chemistry represents an emerging discipline where biomarkers can be analysed within different mediums such as tissue, soil associated with decomposing remains and decomposition fluid. Although advances are being made in these many taphonomic disciplines, the field still has a long way to go in terms of finding the elusive formula for accurately estimating PMI of decomposed remains
Liu, T, Zhang, W, Yuwono, M, Zhang, M, Ueland, M, Forbes, SL & Su, SW 2020, 'A data-driven meat freshness monitoring and evaluation method using rapid centroid estimation and hidden Markov models', SENSORS AND ACTUATORS B-CHEMICAL, vol. 311.View/Download from: Publisher's site
Ueland, M, Brown, A, Bartos, C, Frankham, GJ, Johnson, RN & Forbes, SL 2020, 'Profiling Volatilomes: A Novel Forensic Method for Identification of Confiscated Illegal Wildlife Items', Separations, vol. 7, no. 1, pp. 5-5.View/Download from: Publisher's site
Globally, the rapid decline in wildlife species has many causes. The illegal trafficking of fauna and flora is a major contributor to species decline and continues to grow at an alarming rate. To enable the prosecution of those involved in the trafficking of illegal wildlife, accurate and reliable identification is paramount. Traditionally, morphology and DNA amplification are used. This paper investigates a novel application of volatilome profiling using comprehensive two-dimensional gas chromatography coupled with time of flight mass spectrometry for wildlife sample detection. Known samples of elephant-derived ivory, other dentine samples, and bone (a common ivory substitute) were used as reference samples for volatilome profiling. Subsequently, specimens that were suspected ivory from border control seizures were obtained and analysed. Confirmatory DNA analyses were conducted on seized samples to establish the reliability parameters of volatilome profiling. The volatilome method correctly identified six of the eight seized samples as elephant ivory, which was confirmed through DNA analysis. There was also clear distinction of African elephant ivory parts from the bone and dentine samples from other species, as shown through PCA and discriminant analyses. These preliminary results establish volatilome profiling through GC×GC-TOFMS as a novel screening method used for the identification of unknown wildlife contraband.
Zhang, W, Liu, T, Ueland, M, Forbes, SL, Wang, RX & Su, SW 2020, 'Design of an efficient electronic nose system for odour analysis and assessment', Measurement: Journal of the International Measurement Confederation, vol. 165.View/Download from: Publisher's site
© 2020 Elsevier Ltd This paper presents an efficient electronic nose (e-nose) system, named "NOS.E", for odour analysis and assessment. In addition to the reliable hardware and software designs, an airflow intake system is implemented to ensure the precise odour analysis procedure in the NOS.E system. Additionally, a particular control logic was introduced to improve the test efficiency of the NOS.E by reducing operation time. Furthermore, the fault detection and alarming design can generate a high-reliability performance by constantly monitoring its working status. To evaluate the performance of the NOS.E, three types of alcohols were tested by the NOS.E and compared to data collected by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS). The results indicate that the NOS.E can successfully distinguish three different alcohols with high efficiency and low cost and has the potential to be a universal odour analysis platform implemented in various applications.
Hall, F, Forbes, S, Rowbotham, S & Blau, S 2019, 'Using PMCT of Individuals of Known Age to Test the Suchey-Brooks Method of Aging in Victoria, Australia.', Journal of Forensic Sciences, vol. 64, no. 6, pp. 1782-1787.View/Download from: Publisher's site
The estimation of an individual's age at death plays a critical role in the investigation of unidentified human remains. The Suchey-Brooks method, which involves the analysis of degenerative morphological changes in the pubic symphysis, is currently widely used to estimate age in adults. This study tested the applicability of the Suchey-Brooks method on a contemporary adult Australian (Victorian) subpopulation by observing three-dimensional volume-rendered postmortem computed tomographic (PMCT) reconstructions of the pubic symphysis of 204 individuals aged 15-100 years. Results showed the method was reliable for females (85% correct allocations) but not for males (67% correct allocations). It is therefore recommended that extreme caution be used when applying the Suchey-Brooks method for estimating age at death of an individual in this subpopulation from PMCT images. The results suggest further investigation into alternate age estimation methods is required.
Deo, A, Forbes, SL, Stuart, BH & Ueland, M 2019, 'Profiling the seasonal variability of decomposition odour from human remains in a temperate Australian environment', AUSTRALIAN JOURNAL OF FORENSIC SCIENCES.View/Download from: Publisher's site
Knobel, Z, Ueland, M, Nizio, KD, Patel, D & Forbes, SL 2019, 'A comparison of human and pig decomposition rates and odour profiles in an Australian environment', Australian Journal of Forensic Sciences, vol. 51, no. 5, pp. 557-572.View/Download from: Publisher's site
© 2018 Australian Academy of Forensic Sciences Cadaver-detection dogs are trained to locate victim remains; however, their training is challenging owing to limited access to human remains. Animal analogues, such as pigs, are typically used as alternative training aids. This project aimed to compare the visual decomposition and volatile organic compound (VOC) profile of human and pig remains in an Australian environment, to determine the suitability of pig remains as human odour analogues for cadaver-detection dog training. Four human cadavers and four pig carcasses were placed in an outdoor environment at the Australian Facility for Taphonomic Experimental Research (AFTER) across two seasons. Decomposition was monitored progressively in summer and winter. VOCs were collected onto sorbent tubes and analysed using comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry. Visual observations highlighted the differences in decomposition rates, with pig remains progressing through all stages of decomposition, and human remains undergoing differential decomposition and mummification. Chemical and statistical analysis highlighted variations in the composition and abundance of VOCs over time between the odour profiles. This study concluded that the visual decomposition and VOC profile of pig and human remains was dissimilar. However, in cooler conditions the results from each species became more comparable, especially during the early stages of decomposition.
Liu, T, Zhang, W, Ye, L, Ueland, M, Forbes, SL & Su, SW 2019, 'A novel multi-odour identification by electronic nose using non-parametric modelling-based feature extraction and time-series classification', Sensors and Actuators, B: Chemical, vol. 298.View/Download from: Publisher's site
© 2019 Elsevier B.V. The electronic nose (e-nose) is an olfaction system that consists of an array of chemical sensors and effective machine learning algorithms for the detection of various target odours. Feature extraction and classification methods are of great importance in improving the performance of the e-nose system. In this paper, a novel odour identification method is presented. Firstly, we use the kernel-based system modelling approach to extract odour features. Its solution is a series of finite impulse responses which containing discriminant information of different odours. In addition, a parameter optimisation method based on normalised mean square error and information entropy is proposed to optimise the kernel function. The entropy is effective in preventing the finite impulse responses from overfitting. Multi-odour classification is achieved based on Gaussian mixture density hidden Markov model (GMM-HMM) considering the characteristic of the extracted features. Also, parameter selection for GMM-HMM is realised according to BIC index and cross-validation. Then, we validate the performance of the proposed feature extraction method in resistance to noise and compare it with other existed features. The modelling-based feature reached the highest performance even without applying any filtering or smoothing techniques. Finally, we compare the proposed combination of feature extraction and classification algorithms with other approaches. The proposed method outperformed other approaches reaching 93.56% in sensitivity and 98.71% in specificity. The results demonstrate that the proposed method is applicable in e-nose-based odour identification.
Taranto, V, Ueland, M, Forbes, SL & Blanes, L 2019, 'The analysis of nitrate explosive vapour samples using Lab-on-a-chip instrumentation.', Journal of chromatography. A, vol. 1602, pp. 467-473.View/Download from: Publisher's site
The detection and analysis of explosives and explosive-related compounds is a heightened priority in recent years for homeland security and counter-terrorism applications. This study aimed to evaluate the use of a commercial Lab-On-a-Chip (LOC) instrument for the analysis of explosive vapours, with the long-term goal of developing a portable instrument for passively detecting explosives in air samples. A simple method to collect explosive vapour residues was developed using a glass vial containing varying amounts of the target explosives (1 mg/mL). Standards were diluted to the desired concentration in 150 μL of acetone to facilitate the evaporation. The top of the vial was covered with a circular 0.5 cm diameter filter paper and exposed to a range of temperatures from 22 °C to 80 °C for 15 min. Following evaporation, the filter paper chads were folded and inserted into the LOC wells containing the separation buffer for the analysis, avoiding any further extraction step. After successfully separating and detecting eight explosives via liquid analysis, three explosives were chosen as targets for the vapour analysis experiments. 1,3,5-Trinitrobenzene (TNB), 2,4,6-Trinitrotoluene (TNT), and 2,4,6-Trinitrophenylmethylnitramine (Tetryl) were successfully separated, detected and identified following the vapour extraction of explosive standards onto filter paper chads. Limits of detection for the liquid analysis were demonstrated to be 2.32 ng for TNB, 2.35 ng for Tetryl, and 3.25 ng for TNT. The minimum detectable mass found for the vapour analysis was 6.03 for TNB, 9.99 ng for TNT, and 14.22 ng for Tetryl. The average recovery from the paper chads was 29% for Tetryl, 47% for TNB, and 75% for TNT (n = 4), comparable with findings from previous studies. Results show that a minimum temperature of 40 °C is necessary to vaporize the compounds using acetone, while the best results were achieved when heating the vial to 80 °C. The use of a filter paper to collect the explosi...
Ueland, M, Forbes, SL & Stuart, BH 2019, 'Understanding clothed buried remains: the analysis of decomposition fluids and their influence on clothing in model burial environments.', Forensic science, medicine, and pathology, vol. 15, no. 1, pp. 3-12.View/Download from: Publisher's site
Previous studies of fabric degradation have shown promising results for post-mortem interval estimations based on differences in the degradation states of clothing in the presence of decomposing remains. It is crucial to determine if a body was present when using the degradation state as an indicator of time since death. For this study, fabric samples from buried pig remains were collected and analyzed using attenuated total reflectance Fourier transform infrared spectroscopy and chromatography- mass spectrometry. Three different fabrics were investigated; 100% cotton, 100% polyester and a polyester-cotton blend. Distinct visual changes were observed between the experimental and control graves, with the fabrics in the control grave degrading more rapidly. There was also a difference between the fabric types, whereby the natural fabrics degraded much faster than the synthetic ones. Principal component analysis was used to determine that the cotton control samples could be statistically separated based on their degradation state. The presence of lipids and proteins were useful for separating "wetter" graves from those drier in nature as well as the control graves. Clothing evidence was demonstrated to provide quantitative time since death information, as well as indicating the decomposition site in the event of intentional or unintentional movement.
Zhang, W, Liu, T, Ye, L, Ueland, M, Forbes, SL & Su, SW 2019, 'A novel data pre-processing method for odour detection and identification system', Sensors and Actuators, A: Physical, vol. 287, pp. 113-120.View/Download from: Publisher's site
© 2018 Elsevier B.V. This paper presents a novel electronic nose (E-nose) data pre-processing method, based on a recently developed non-parametric kernel-based modelling (KBM) approach. The proposed method is tested by an automated odour detection and classification system, named "NOS.E" developed by the NOS.E team in University of Technology Sydney. Experimental results show that when extracting the derivative-related features from signals collected by the NOS.E, the proposed non-parametric KBM odour data pre-processing method achieves more reliable and stable pre-processing results comparing with other pre-processing methods such as wavelet package correlation filter (WPCF), mean filter (MF), polynomial curve fitting (PCF) and locally weighted regression (LWR). Based on these derivative-related features, the NOS.E can achieve a 96.23% accuracy of classification with the popular Support Vector Machine (SVM) classifier.
Buis, R, Rust, L, Nizio, KD, Rai, T, Stuart, BH & Forbes, SL 2019, 'Investigating the Sensitivity of Cadaver- Detection Dogs to Aged, Diluted Decomposition Fluid', Journal of Forensic Identification, vol. 69, no. 3, pp. 367-377.
Cadaver-detection dogs (also known as human remains detection dogs) are used worldwide to locate deceased victims and human remains. Ethical restrictions often prevent the dog handlers from using cadavers as training aids, resulting in a reliance on pseudo-scents or human tissues, such as blood, bone, and decomposition fluid. Often these aids must be re-used many times because of the difficulty in obtaining new materials. The aim of this study was to investigate the dogs' sensitivity to aged human decomposition fluid samples that are used as a training aid. Human decomposition fluid was collected and serially diluted to 1 part-per-trillion (10u) and aged up to two years. The samples were presented throughout the aging process to three police accredited cadaver-detectior. dog teams under standard indoor training conditions. The dogs were capable of detecting the oldest and lowest dilution levels of decomposition fluid samples. Ongoing training to retain this level of sensitivity is recommended. The results of these trials indicate human decomposition fluid is a valid training aid for cadaver-detection dogs.
Huston, WM, Cranfield, CG, Forbes, SL & Leigh, A 2019, 'A sponsorship action plan for increasing diversity in STEMM.', Ecology and Evolution, vol. 9, no. 5, pp. 2340-2345.View/Download from: Publisher's site
There are numerous structural and cultural barriers to the progression of women and marginalized groups to leadership in academia, especially in Science, Technology, Engineering, Mathematics and Medicine (STEMM). A range of interventions have been described to address this inequity, with varying success. Here, we suggest that sponsorship could be one effective intervention and propose an institutional action plan to implement a sponsorship program in academia. We outline why sponsorship could be an effective strategy, especially if implemented through a deliberate program by an institution. We then detail the three components of an action plan to be considered in implementation: the elements of the program, the activities that sponsorship in academia likely encompasses, and the selection of sponsors and protégés. The plan could also be enacted by academic leadership in the absence of an institutional program and could serve as a guide to individuals in academia aspiring to address diversity and inclusion in STEMM.
Leung, D, Forbes, S & Maynard, P 2019, 'Volatile organic compound analysis of accelerant detection canine distractor odours.', Forensic science international, vol. 303.View/Download from: Publisher's site
Ignitable liquid detection dogs have been observed to falsely-respond to the pyrolysis products of common burned household items such as carpets and garden hoses, where ignitable liquids were not present. These responses from the canines are described as coming from distractor odours and decrease the reliability of detector dogs. The purpose of this research was to study the volatile organic compounds (VOCs) present in the odour profile of pyrolysed carpet and garden hose substrates, and determine whether a chemical similarity exists between these pyrolysis headspace profiles and target ignitable liquids, which may explain the false-positive behaviour of these detector dogs. Garden hose and carpet samples obtained from domestic settings were heated at a constant temperature for a specified time to produce pyrolysis products. A solid-phase microextraction (SPME) method was developed to extract the VOCs from burned substrates. The odours of the burned substrates were analysed by gas chromatography-mass spectrometry (GC/MS) and gas chromatography-tandem mass spectrometry (GC/MS/MS). A GC-MS/MS method was developed targeting the characteristic aromatic compounds in gasoline. Each pyrolysed substrate produced a complex and unresolved odour profile when analysed by GC- MS. GC-MS analysis failed to find any similarities between the odours of the burned substrates and ignitable liquids. GC-MS/MS analysis of pyrolysed garden hose and carpet substrate odours resolved and identified a wide range of aromatic target compounds - and these were present in high abundances in the hose samples. This indicates that there are significant chemical similarities between vapours of ignitable liquids and their distractor odours, which will have implications for the training of ignitable liquid detector dogs.
Rust, LT, Nizio, KD, Wand, MP & Forbes, SL 2018, 'Investigating the detection limits of scent-detection dogs to residual blood odour on clothing', Forensic Chemistry, vol. 9, pp. 62-75.View/Download from: Publisher's site
© 2018 Elsevier B.V. Blood-detection dogs are trained to locate blood evidence and search for potential crime scenes in cases where a cadaver may not be present. The locations of crime scenes are often ambiguous and evidence may not always be obvious during initial processing. In cases of foul play, a criminal may attempt to clean biological evidence from a crime scene; however, trace evidence that appears invisible to the naked eye may still be detectable. For example, it has been reported anecdotally that blood-detection dogs are capable of detecting blood on clothing that has been washed up to five times, or on surfaces which have been scrubbed clean. This study aimed to investigate the baseline detection limits of blood-detection dogs and cadaver-detection dogs to latent blood evidence on washed clothing and to compare the dogs' responses to current presumptive chemical and analytical techniques. Blood was deposited onto cotton swatches and washed up to five times with a standard household washing machine. Following washing, the cotton swatches were allowed to dry and presented to blood-detection and cadaver-detection dogs during law enforcement training. Replicates of these samples were tested with luminol spray and analysed using headspace solid phase microextraction – comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (HS-SPME-GC×GC-TOFMS). Results indicated that the olfactory system of blood-detection and cadaver-detection dogs is a viable complementary technique to presumptive chemical tests and more sensitive than current scientific instrumentation, with some of the dogs able to detect blood after five washes but HS-SPME-GC×GC-TOFMS only able to detect blood after two washes or less. This limit of detection could likely be lowered for the dogs with further and more consistent training. Luminol was similarly able to detect blood washed up to five times, which indicates that the scenting abilities of these dogs can provide...
Chilcote, B, Rust, L, Nizio, KD & Forbes, SL 2018, 'Profiling the scent of weathered training aids for blood-detection dogs.', Science and Justice - Journal of the Forensic Science Society, vol. 58, no. 2, pp. 98-108.View/Download from: Publisher's site
At outdoor crime scenes, cadaver-detection and blood-detection dogs may be tasked with locating blood that is days, weeks or months old. Although it is known that the odour profile of blood will change during this time, it is currently unknown how the profile changes when exposed to the environment. Such variables must be studied in order to understand when the odour profile is no longer detectable by the scent-detection dogs and other crime scene tools should be implemented. In this study, blood was deposited onto concrete and varnished wood surfaces and weathered in an outdoor environment over a three-month period. Headspace samples were collected using solid phase microextraction (SPME) and analysed using comprehensive two-dimensional gas chromatography - time-of-flight mass spectrometry (GC×GC-TOFMS). The chemical odour profiles were compared with the behavioural responses of cadaver-detection and blood-detection dogs during training. Data interpretation using principal component analysis (PCA) and hierarchical cluster analysis (HCA) established that the blood odour could no longer be detected using SPME-GC×GC-TOFMS after two months of weathering on both surfaces. Conversely, the blood-detection dogs had difficulty locating the blood samples after one month of weathering on concrete and after one week of weathering on varnished wood. The scent-detection dogs evaluated herein had not been previously exposed to environmentally weathered blood samples during training. Given that this study was conducted to test the dogs' baseline abilities, it is expected that with repeated exposure, the dogs' capabilities would likely improve. The knowledge gained from this study can assist in providing law enforcement with more accurate training aids for blood-detection dogs and can improve their efficiency when deployed to outdoor crime scenes.
Hayes, JE, McGreevy, PD, Forbes, SL, Laing, G & Stuetz, RM 2018, 'Critical review of dog detection and the influences of physiology, training, and analytical methodologies.', Talanta, vol. 185, pp. 499-512.View/Download from: Publisher's site
Detection dogs serve a plethora of roles within modern society, and are relied upon to identify threats such as explosives and narcotics. Despite their importance, research and training regarding detection dogs has involved ambiguity. This is partially due to the fact that the assessment of effectiveness regarding detection dogs continues to be entrenched within a traditional, non-scientific understanding. Furthermore, the capabilities of detection dogs are also based on their olfactory physiology and training methodologies, both of which are hampered by knowledge gaps. Additionally, the future of detection dogs is strongly influenced by welfare and social implications. Most importantly however, is the emergence of progressively inexpensive and efficacious analytical methodologies including gas chromatography related techniques, "e-noses", and capillary electrophoresis. These analytical methodologies provide both an alternative and assistor for the detection dog industry, however the interrelationship between these two detection paradigms requires clarification. These factors, when considering their relative contributions, illustrate a need to address research gaps, formalise the detection dog industry and research process, as well as take into consideration analytical methodologies and their influence on the future status of detection dogs. This review offers an integrated assessment of the factors involved in order to determine the current and future status of detection dogs.
Luong, S, Forbes, SL, Wallman, JF & Roberts, RG 2018, 'Monitoring the extent of vertical and lateral movement of human decomposition products through sediment using cholesterol as a biomarker.', Forensic science international, vol. 285, pp. 93-104.View/Download from: Publisher's site
Due to the lack of human decomposition research facilities available in different geographical regions, the extent of movement of human decomposition products from a cadaver into various sedimentary environments, in different climates, has not been able to be studied in detail. In our study, a human cadaver was placed on the surface of a designated plot at the Australian Facility for Taphonomic Experimental Research (AFTER), the only human decomposition facility in Australia, where the natural process of decomposition was allowed to progress over 14days in the Australian summer. Sediment columns (approximately 1m deep) were collected at lateral distances of 0.25m, 0.5m, 1.0m and 2.5m in each of four directions from the centre of the torso. Plot elevation and weather data were also collected. Each sediment column was subdivided, dried and homogenised. A sample was isolated from each sediment subdivision, extracted with hexane, and the hexane extract cleaned with citrate buffer (pH 3), filtered and spiked with cholesterol-D7 internal standard. After derivatisation with BSTFA+1% TMCS, cholesterol was monitored in the samples using targeted gas chromatography tandem mass spectrometry analysis. A positive result for decomposition products was given if the cholesterol abundance in the test sample was higher than that detected in the 'control' samples of a similar substrate type collected prior to cadaver placement. Within the confines of the experimental design and the measured parameters, lateral leaching was observed over distances of up to 2.5m from the centre of the torso, which was the maximum distance tested in the study. Vertical leaching was detected to depths of up to 49cm below the ground surface. Such data can aid the development of policies related to plot sizing and sediment renewal and regeneration at other human decomposition facilities and at cemeteries. The density and distribution of cholesterol surrounding the cadaver in this study can also help fore...
Marhoff-Beard, SJ, Forbes, SL & Green, H 2018, 'The validation of 'universal' PMI methods for the estimation of time since death in temperate Australian climates', FORENSIC SCIENCE INTERNATIONAL, vol. 291, pp. 158-166.View/Download from: Publisher's site
Nizio, K & Forbes, S 2018, 'Developing a Method for the Collection and Analysis of Burnt Remains for the Detection and Identification of Ignitable Liquid Residues Using Body Bags, Dynamic Headspace Sampling, and TD-GC×GC-TOFMS', Separations, vol. 5, no. 3, pp. 46-46.View/Download from: Publisher's site
In cases of suspected arson, a body may be intentionally burnt to cause loss of life, dispose of remains, or conceal identification. A primary focus of a fire investigation, particularly involving human remains, is to establish the cause of the fire; this often includes the forensic analysis of fire debris for the detection of ignitable liquid residues (ILRs). Commercial containers for the collection of fire debris evidence include metal cans, glass jars, and polymer/nylon bags of limited size. This presents a complication in cases where the fire debris consists of an intact, or partially intact, human cadaver. This study proposed the use of a body bag as an alternative sampling container. A method was developed and tested for the collection and analysis of ILRs from burnt porcine remains contained within a body bag using dynamic headspace sampling (using an Easy-VOC™ hand-held manually operated grab-sampler and stainless steel sorbent tubes containing Tenax TA) followed by thermal desorption comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (TD-GC×GC-TOFMS). The results demonstrated that a body bag containing remains burnt with gasoline tested positive for the presence of gasoline, while blank body bag controls and a body bag containing remains burnt without gasoline tested negative. The proposed method permits the collection of headspace samples from burnt remains before the remains are removed from the crime scene, limiting the potential for contamination and the loss of volatiles during transit and storage.
Liu, T, Zhang, W, McLean, P, Ueland, M, Forbes, SL & Su, SW 2018, 'Electronic Nose-Based Odor Classification using Genetic Algorithms and Fuzzy Support Vector Machines', International Journal of Fuzzy Systems, vol. 20, no. 4, pp. 1309-1320.View/Download from: Publisher's site
© 2018, Taiwan Fuzzy Systems Association and Springer-Verlag GmbH Germany, part of Springer Nature. Electronic nose devices consisting of a matrix of sensors to sense the smell of various target gases have received considerable attention during the past two decades. This paper presents an efficient classification algorithm for a self-designed electronic nose, which integrates both genetic algorithms (GAs) and fuzzy support vector machines (FSVMs) to detect the target odor. GAs are applied to select the informative features and the optimal model parameters of FSVMs. FSVMs are adopted as fitness evaluation criterion and the sequent odor classifier, which can reduce the outlier effects and provide a robust and accurate classification. This proposed algorithm has been compared with some commonly used learning algorithms, such as support vector machine, the k-nearest neighbors and other combination algorithms. This study is based on experimental data collected from the response of the UTS NOS.E, which is the electronic nose system developed by the University of Technology Sydney NOS.E team. In comparison with other approaches, the experiment results show that the proposed odor classification algorithm can significantly improve the classification accuracy by selecting high-quality features and reach to 92.05% classification accuracy.
Ueland, M, Forbes, SL & Stuart, BH 2018, 'Seasonal variation of fatty acid profiles from textiles associated with decomposing pig remains in a temperate Australian environment', Forensic Chemistry, vol. 11, pp. 120-127.View/Download from: Publisher's site
© 2018 Elsevier B.V. A methodology to examine the human post-mortem decomposition process has been developed through the monitoring of chemical changes to decomposition fluids absorbed by clothing. Model surface burials using clothed pigs were established during summer and winter seasons in a temperate region of Australia. Three clothing materials were investigated: cotton, polyester and cotton-polyester. Lipid decomposition products were extracted from the textiles and the fatty acid composition measured as a function of burial time using gas chromatography – mass spectrometry (GC-MS). Two derivatisation methods for the fatty acids were compared to establish the most effective approach and it was established that a trimethylsilylation derivatisation method is the optimal preparation technique. The summer trials revealed two rates of transformation of fatty acids from unsaturated to saturated forms, with a faster rate of change occurring earlier in the trials. A different pattern of behaviour was observed for the fatty acids detected during the winter trial, with a decrease in saturated fatty acids initially observed, followed by the conversion of unsaturated to saturated fatty acids until the end of trial. The initial change observed during the winter trial was attributed to a dehydrogenation process caused by microbiological enyzymatic activity. The study has demonstrated the feasibility of examining lipid decomposition products collected in clothing from burials to provide insight into the conditions and length of burial.
Di Maggio, RM, Donnelly, LJ, Al Naimi, KS, Barone, PM, Da Silva Salvador, FA, Dawson, L, Dixon, R, Fitzpatrick, R, Gradusova, O, Nesterina, E, Peleneva, M, Ushacova, O, Gallego, CMM, Pirrie, D, Ruffell, A, McKinley, J, Sagripanti, G, Villalba, D, Schneck, B, Sugita, R, Wach, G, Silva, R & Forbes, S 2017, 'Global developments in forensic geology', Episodes, vol. 40, no. 2, pp. 120-131.View/Download from: Publisher's site
Forensic geology has developed in each country dependent on the history, political and social setting, anthropological influences and geology. The aim of this section is to provide a global overview of forensic geology, including the history, developments and future challenges in Africa, Asia, Australia, Canada, Europe, Middle East, Latin America and the Caribbean, Russia and Commonwealth Independent States (CIS), and USA.
O'Brien, RC, Appleton, AJ & Forbes, SL 2017, 'Comparison of taphonomic progression due to the necrophagic activity of geographically disparate scavenging guilds', Journal of the Canadian Society of Forensic Science, vol. 50, no. 1, pp. 42-53.View/Download from: Publisher's site
© 2016 Canadian Society of Forensic Science. Taphonomy, the study of the progression of living things from death to decay or fossilization, is crucial for understanding and determining the post mortem interval. One of the many factors that influence the taphonomic development of a set of remains is scavenger activity. Animals that feed on a carcass can greatly influence the interpretation of the circumstances which have led to the deposition of the body, thus it is important to be able to characterise how necrophagy impacts decomposition. Because the species of scavengers vary greatly depending on the region, information must be gathered in different areas that can provide generalizations for diverse geographic locations. This study seeks to characterise and compare the decomposition rates of remains in Western Australia and in Ontario, Canada. Domestic pig (Sus scrofa) carcasses were placed in four locations near Perth, Western Australia and in two locations in Ontario, Canada. These were observed using trail cameras to document scavenging activity and the progression of decay. The results showed that even when climatic variable are taken into account, the effects of scavenging on decompositional rates are significant. Information from this research provides insight into the influence of distinct scavenging guilds on decomposition and how understanding the necrophagy of local fauna may contribute to the interpretation of a death scene.
Verheggen, F, Perrault, KA, Megido, RC, Dubois, LM, Francis, F, Haubruge, E, Forbes, SL, Focant, JF & Stefanuto, PH 2017, 'The Odor of Death: An Overview of Current Knowledge on Characterization and Applications', Bioscience, vol. 67, no. 7, pp. 600-613.View/Download from: Publisher's site
© 2017 The Author(s). After death, the human body undergoes various processes that result in the emission of volatile organic compounds (VOCs). The interest in these VOCs has increased substantially in recent years because they are key attractants for necrophagous insects and vertebrate scavengers. Identifying cadaveric VOCs has required the effective development of analytical tools for collecting, separating, identifying, and quantifying the suite of VOCs released throughout decomposition. Analytical developments for studying cadaveric VOCs in vertebrates, ecological interactions of cadaveric VOCs with the abiotic and biotic environment, and the necessity for convergence of these two areas for the progression of future knowledge are discussed herein.
Iqbal, MA, Nizio, KD, Ueland, M & Forbes, SL 2017, 'Forensic decomposition odour profiling: A review of experimental designs and analytical techniques', TrAC - Trends in Analytical Chemistry, vol. 91, pp. 112-124.View/Download from: Publisher's site
© 2017 Elsevier B.V. The complex process of cadaveric decomposition releases diverse volatile organic compounds (VOCs) as by-products. These VOCs are significant in forensic science as the odour they comprise can be tracked by trained canines when searching for human remains in cases of missing persons, homicide, or mass disaster. Although this is an emerging area of research, numerous studies have been conducted to form a greater understanding of decomposition odour and its range of applications. While some of these studies are conducted in laboratories, most are conducted at specialised field sites (e.g., forensic, archaeological, taphonomic, search and rescue training facilities). This paper reviews these studies to provide a critical overview of the experimental approaches and analytical techniques used in decomposition odour analysis. Discussion covers the outcomes of these studies, their contribution to the field, and future directions, particularly the advances in analytical instrumentation currently being employed to provide a comprehensive decomposition odour profile.
Nizio, KD, Ueland, M, Stuart, BH & Forbes, SL 2017, 'The analysis of textiles associated with decomposing remains as a natural training aid for cadaver-detection dogs', Forensic Chemistry, vol. 5, pp. 33-45.View/Download from: Publisher's site
© 2017 Elsevier B.V. Cadaver-detection dogs are employed by law enforcement agencies to locate human remains in cases of missing persons, suspected homicides and following natural or man-made disasters. The ability of cadaver-detection dogs to locate human remains relies heavily on the use of effective and reliable training aids. Cadaver-detection dogs may be trained using a variety of materials ranging from natural scent sources (e.g. flesh, bone, blood or decomposition soil) to synthetic materials (e.g. Pseudo™ Scents). Commercially available synthetic scents often have an overly simplistic chemical composition that is inconsistent with decomposition odour. Therefore, natural scent sources are typically considered to be the most effective training aids; however, there is concern that using individual tissue types as natural training aids may not be indicative of the scent of an intact human cadaver. The objective of this work was to determine how well textiles associated with decomposing remains retain and mimic the odour of natural training aids. To test this, the chemical odour profile of textile samples collected from decomposing porcine remains that were buried clothed in 100% cotton t-shirts was examined. Throughout various stages of decomposition, the pig carcasses were exhumed and cotton samples were obtained. The volatile organic compound (VOC) profile of the textiles was collected using headspace solid phase microextraction (HS-SPME) and analysed using comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GC×GC-TOFMS). This study provides evidence that textiles associated with decomposing remains may represent a useful natural training aid with a VOC profile reflective of a large subset of cadaveric decomposition odour. The odour profile is dynamic and changes over time suggesting that obtaining textiles from different postmortem intervals would be useful for providing training aids that represent the full spectrum of dec...
Ueland, M, Howes, JM, Forbes, SL & Stuart, BH 2017, 'Degradation patterns of natural and synthetic textiles on a soil surface during summer and winter seasons studied using ATR-FTIR spectroscopy.', Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 185, pp. 69-76.View/Download from: Publisher's site
Textiles are a valuable source of forensic evidence and the nature and condition of textiles collected from a crime scene can assist investigators in determining the nature of the death and aid in the identification of the victim. Until now, much of the knowledge of textile degradation in forensic contexts has been based on the visual inspection of material collected from soil environments. The purpose of the current study was to investigate the potential of a more quantitative approach to the understanding of forensic textile degradation through the application of infrared spectroscopy. Degradation patterns of natural and synthetic textile materials as they were subjected to a natural outdoor environment in Australia were investigated. Cotton, polyester and polyester - cotton blend textiles were placed on a soil surface during the summer and winter seasons and were analysed over periods 1 and 1.5years, respectively, and examined using attenuated total reflectance (ATR) spectroscopy. Statistical analysis of the spectral data obtained for the cotton material correlated with visual degradation and a difference in the onset of degradation between the summer and winter season was revealed. The synthetic material did not show any signs of degradation either visually or statistically throughout the experimental period and highlighted the importance of material type in terms of preservation. The cotton section from the polyester - cotton blend samples was found to behave in a similar manner to that of the 100% cotton samples, however principal component analysis (PCA) demonstrated that the degradation patterns were less distinct in both the summer and winter trial for the blend samples. These findings indicated that the presence of the synthetic material may have inhibited the degradation of the natural material. The use of statistics to analyse the spectral data obtained for textiles of forensic interest provides a better foundation for the interpretation of the data o...
Armstrong, P, Nizio, KD, Perrault, KA & Forbes, SL 2016, 'Establishing the volatile profile of pig carcasses as analogues for human decomposition during the early postmortem period', Heliyon, vol. 2, no. 2.View/Download from: Publisher's site
Breton, H, Kirkwood, AE, Carter, DO & Forbes, SL 2016, 'The impact of carrion decomposition on the fatty acid methyl ester (FAME) profiles of soil microbial communities in southern Canada', Journal of the Canadian Society of Forensic Science, vol. 49, no. 1, pp. 1-18.View/Download from: Publisher's site
© 2015 Canadian Society of Forensic Science Profiling microbial communities associated with cadaver decomposition may provide useful information concerning post-mortem intervals and aid in the identification of clandestine graves. Four experiments using pig carcasses as human decomposition analogues were performed over the course of 2011 and 2012 in southern Ontario to document changes in soil microbiology following decomposition. Studies were conducted in both spring and summer to determine the effect of environmental variables on the decomposition process and subsequent changes in gravesoil microbiology. Fatty acid methyl ester (FAME) profiling was used to investigate the community level changes in soil throughout the decomposition process. Shifts in FAME profiles coincided with the onset of active decay and persisted through to the dry remains stage. Results also indicated that FAME profiles differed between seasons and years. These studies highlight the need to document natural changes in microbial communities over seasons and years to establish normal soil profiles and patterns to effectively use this analysis as a tool for post-mortem interval estimation or for locating clandestine graves.
Marhoff, SJ, Fahey, P, Forbes, SL & Green, H 2016, 'Estimating post-mortem interval using accumulated degree-days and a degree of decomposition index in Australia: a validation study', AUSTRALIAN JOURNAL OF FORENSIC SCIENCES, vol. 48, no. 1, pp. 24-36.View/Download from: Publisher's site
Nizio, KD, Cochran, JW & Forbes, SL 2016, 'Achieving a Near-Theoretical Maximum in Peak Capacity Gain for the Forensic Analysis of Ignitable Liquids Using GC×GC-TOFMS', Separations, vol. 3, no. 3.View/Download from: Publisher's site
At present, gas chromatography–quadrupole mass spectrometry (GC-qMS) is considered the gold standard amongst analytical techniques for fire debris analysis in forensic laboratories worldwide, specifically for the detection and classification of ignitable liquids. Due to the highly complex and unpredictable nature of fire debris, traditional one-dimensional GC-qMS often produces chromatograms that display an unresolved complex mixture containing only trace levels of the ignitable liquid among numerous background pyrolysis products that interfere with pattern recognition necessary to verify the presence and identification of the ignitable liquid. To combat these challenges, this study presents a method optimized to achieve a near-theoretical maximum in peak capacity gain using comprehensive two-dimensional gas chromatography (GC×GC) coupled to time-of-flight mass spectrometry (TOFMS) for the forensic analysis of petroleum-based ignitable liquids. An overall peak capacity gain of 9.3 was achieved, which is only 17% below the system's theoretical maximum of 11.2. In addition, through the preservation of efficient separation in the first dimension and optimal stationary phase selection in the second dimension, the presented method demonstrated improved resolution, enhanced sensitivity, increased peak detectability and structured chromatograms well-suited for the rapid classification of ignitable liquids. As a result, the method generated extremely detailed fingerprints of petroleum-based ignitable liquids including gasoline, kerosene, mineral spirits and diesel fuel. The resultant data was also shown to be amenable to chromatographic alignment and multivariate statistical analysis for future evaluation of chemometric models for the rapid, objective and automated classification of ignitable liquids in fire debris extracts.
Perrault, KA & Forbes, SL 2016, 'Elemental analysis of soil and vegetation surrounding decomposing human analogues', Journal of the Canadian Society of Forensic Science, vol. 49, no. 3, pp. 138-151.View/Download from: Publisher's site
© 2016 Canadian Society of Forensic ScienceThe introduction of cadaveric material creates a localized surge of nutrients into the surrounding environment, which can have a profound effect on soil and vegetation in contact with the cadaver. Nutrient dynamics may assist in identifying the original deposition site of remains when scavenging has occurred, or where remains have been relocated to a secondary site in an attempt at concealment. The aim of this study was to characterize the nutrient input into the soil and vegetation surrounding decomposing pig (Sus scrofa domesticus) carcasses at an outdoor decomposition research facility in Southern Ontario. Soil and vegetation (Agrostis gigantea) samples were collected in a 2 m radial pattern from the carcasses. Significant elevation of percent water holding capacity, pH, soil-available phosphorus, and sodium were identified within a 20 cm radius and on occasion at 50 cm over three months. Potassium, calcium, and magnesium remained at baseline levels throughout the study. Increased nutrient availability could not be identified outside of the cadaver decomposition island (CDI), suggesting that nutrients may not easily pass through the CDI perimeter. Increased nutrient availability introduced by decomposing remains provides a means of chemical characterization of their original location, and could provide valuable information in death investigations.
Rust, L, Nizio, KD & Forbes, SL 2016, 'The influence of ageing and surface type on the odour profile of blood-detection dog training aids', Analytical and Bioanalytical Chemistry, vol. 408, no. 23, pp. 6349-6360.View/Download from: Publisher's site
Cadaver-detection dogs are a preferred search tool utilised by law enforcement agencies for the purposes of locating victim remains due to their efficiency and minimal disturbance to the crime scene. In Australia, a specific group of these canines are blood-detection dogs, which are trained to detect and locate blood evidence and search potential crime scenes in cases where a cadaver may not be present. Their role sometimes requires searches to be carried out after considerable time has passed since the crime occurred, and this is important for developing effective training protocols. This study aimed to investigate the volatile organic compounds (VOCs) produced from fresh and aged human blood on various surfaces. Solid phase microextraction (SPME) was used to extract VOCs from the headspace of dried blood samples aged and sampled periodically over 12 months from a non-porous (i.e. aluminium) and porous (i.e. cotton) surface. Samples were analysed using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC-TOFMS). Fresh blood produced distinctively different VOC patterns compared to blood aged longer than 1 week with the overall profile differing between the two surface types, and a large subset of the VOC profile found to be responsible for these differences. When analysing the various functional groups present in the samples, a common pattern between ages and surface types was observed with no specific chemical class dominating the overall profile. The results highlight the importance of evaluating training aids for scent-detection canines to ensure the greatest efficacy during training and subsequently at crime scene searches.
Forbes, SL, Troobnikoff, AN, Ueland, M, Nizio, KD & Perrault, KA 2016, 'Profiling the decomposition odour at the grave surface before and after probing', Forensic Science International, vol. 259, pp. 193-199.View/Download from: Publisher's site
Human remains detection (HRD) dogs are recognised as a valuable and non-invasive search method for remains concealed in many different environments, including clandestine graves. However, the search for buried remains can be a challenging task as minimal odour may be available at the grave surface for detection by the dogs. Handlers often use a soil probe during these searches in an attempt to increase the amount of odour available for detection, but soil probing is considered an invasive search technique. The aim of this study was to determine whether the soil probe assists with increasing the abundance of volatile organic compounds (VOCs) available at the grave surface. A proof-of-concept method was developed using porcine remains to collect VOCs within the grave without disturbing the burial environment, and to compare their abundance at the grave surface before and after probing. Detection and identification of the VOC profiles required the use of comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC–TOFMS) due to its superior sensitivity and selectivity for decomposition odour profiling. The abundance of decomposition VOCs was consistently higher within the grave environment compared to the grave surface, except when the grave surface had been disturbed, confirming the reduced availability of odour at the grave surface. Although probing appeared to increase the abundance of VOCs at the grave surface on many of the sampling days, there were no clear trends identified across the study and no direct relationships with the environmental variables measured. Typically, the decomposition VOCs that were most prevalent in the grave soil were the same VOCs detected at the grave surface, whereas the trace VOCs detected in these environments varied throughout the post-burial period. This study highlighted that probing the soil can assist with releasing decomposition VOCs but is likely correlated to environmental and burial variables wh...
Nizio, KD, Perrault, KA, Troobnikoff, AN, Ueland, M, Shoma, S, Iredell, JR, Middleton, PG & Forbes, SL 2016, 'In vitro volatile organic compound profiling using GC×GC-TOFMS to differentiate bacteria associated with lung infections: a proof-of-concept study', Journal of Breath Research, vol. 10.View/Download from: Publisher's site
Chronic pulmonary infections are the principal cause of morbidity and mortality in individuals with cystic fibrosis (CF). Due to the polymicrobial nature of these infections, the identification of the particular bacterial species responsible is an essential step in diagnosis and treatment. Current diagnostic procedures are time-consuming, and can also be expensive, invasive and unpleasant in the absence of spontaneously expectorated sputum. The development of a rapid, non-invasive methodology capable of diagnosing and monitoring early bacterial infection is desired. Future visions of real-time, in situ diagnosis via exhaled breath testing rely on the differentiation of bacteria based on their volatile metabolites. The objective of this proof-of-concept study was to investigate whether a range of CF-associated bacterial species (i.e. Pseudomonas aeruginosa, Burkholderia cenocepacia, Haemophilus influenzae, Stenotrophomonas maltophilia, Streptococcus pneumoniae and Streptococcus milleri) could be differentiated based on their in vitro volatile metabolomic profiles. Headspace samples were collected using solid phase microextraction (SPME), analyzed using comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GC×GC-TOFMS) and evaluated using principal component analysis (PCA) in order to assess the multivariate structure of the data. Although it was not possible to effectively differentiate all six bacteria using this method, the results revealed that the presence of a particular pattern of VOCs (rather than a single VOC biomarker) is necessary for bacterial species identification. The particular pattern of VOCs was found to be dependent upon the bacterial growth phase (e.g. logarithmic vs. stationary) and sample storage conditions (e.g. short-term vs. long-term storage at -18 °C). Future studies of CF-associated bacteria and exhaled breath condensate will benefit from the approaches presented in this study and further facilitate the p...
Ueland, M, Ewart, K, Troobnikoff, AN, Frankham, G, Johnson, RN & Forbes, SL 2016, 'A rapid chemical odour profiling method for the identification of rhinoceros horns.', Forensic science international, vol. 266, pp. 99-102.View/Download from: Publisher's site
Illegal poaching causes great harm to species diversity and conservation. A vast amount of money is involved in the trade of illegal or forged animal parts worldwide. In many cases, the suspected animal part is unidentifiable and requires costly and invasive laboratory analysis such as isotopic fingerprinting or DNA testing. The lack of rapid and accurate methods to identify wildlife parts at the point of detection represents a major hindrance in the enforcement and prosecution of wildlife trafficking. The ability of wildlife detector dogs to alert to different wildlife species demonstrates that there is a detectable difference in scent profile of illegally traded animal parts. This difference was exploited to develop a rapid, non-invasive screening method for distinguishing rhinoceros horns of different species. The method involved the collection of volatile organic compounds (VOC) by headspace solid-phase microextraction (HS-SPME) and analysis by comprehensive two-dimensional gas chromatography - time-of-flight mass spectrometry (GC×GC-TOFMS). It was hypothesised that the use of the specific odour profile as a screening method could separate and differentiate geographic origin or exploit the difference in diets of different species within a family (such as white rhinoceros and black rhinoceros from the Rhinocerotidae family). Known black and white rhinoceros horn samples were analysed using HS-SPME-GC×GC-TOFMS and multivariate statistics were applied to identify groupings in the data set. The black rhinoceros horn samples were distinctly different from the white rhinoceros horn samples. This demonstrated that seized rhinoceros horn samples can be identified based on their distinct odour profiles. The chemical odour profiling method has great potential as a rapid and non-invasive screening method in order to combat and track illegal trafficking of wildlife parts.
Wenholz, DS, Luong, S, Philp, M, Forbes, SL, Stuart, BH, Drummer, OH & Fu, S 2016, 'A study to model the post-mortem stability of 4-MMC, MDMA and BZP in putrefying remains', FORENSIC SCIENCE INTERNATIONAL, vol. 265, pp. 54-60.View/Download from: Publisher's site
Chun, LP, Miguel, MJ, Junkins, EN, Forbes, SL & Carter, DO 2015, 'An initial investigation into the ecology of culturable aerobic postmortem bacteria', Science and Justice, vol. 55, no. 6, pp. 394-401.View/Download from: Publisher's site
© 2015 The Chartered Society of Forensic Sciences. Postmortem microorganisms are increasingly recognized for their potential to serve as physical evidence. Yet, we still understand little about the ecology of postmortem microbes, particularly those associated with the skin and larval masses. We conducted an experiment to characterize microbiological and chemical properties of decomposing swine (Sus scrofa domesticus) carcasses on the island of Oahu, Hawaii, USA, during June 2013. Bacteria were collected from the head, limb, and larval mass during the initial 145. h of decomposition. We also measured the pH, temperature, and oxidation-reduction potential of larval masses in situ. Bacteria were cultured aerobically on Standard Nutrient Agar at 22. °C and identified using protein or genetic signals. Carcass decomposition followed a typical sigmoidal pattern and associated bacterial communities differed by sampling location and time since death, although all communities were dominated by phyla Actinobacteria, Firmicutes, and Proteobacteria. Larval masses were reducing environments (~-200. mV) of neutral pH (6.5-7.5) and high temperature (35. °C-40. °C). We recommend that culturable postmortem and larval mass microbiology and chemistry be investigated in more detail, as it has potential to complement culture-independent studies and serve as a rapid estimate of PMI.
Comstock, J, Desaulniers, J-P, LeBlanc, H & Forbes, S 2015, 'New decomposition stages to describe scenarios involving the partial and complete exclusion of insects', CANADIAN SOCIETY OF FORENSIC SCIENCE JOURNAL, vol. 48, no. 1, pp. 1-19.View/Download from: Publisher's site
Perrault, K, Nizio, K & Forbes, S 2015, 'A Comparison of One-Dimensional and Comprehensive Two-Dimensional Gas Chromatography for Decomposition Odour Profiling Using Inter-Year Replicate Field Trials', Chromatographia, vol. 78, no. 15-16, pp. 1057-1070.View/Download from: Publisher's site
Decomposition odour analysis involves the chemical profiling of volatile organic compounds produced by decomposing remains. This is important for areas of forensic science that rely on the detection of decomposition odour such as insect attraction to carrion, positive alerts of cadaver dogs to decomposing remains, and the development of field instrumentation for search and recovery procedures. Traditionally decomposition odour analysis has been performed using gas chromatography–quadrupole mass spectrometry (GC–qMS); however, the use of comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC–TOFMS) is rapidly becoming more prevalent. The objective of this study was to compare GC–qMS and GC×GC–TOFMS for decomposition odour profiling based on inter-year replicate field studies using decomposing porcine remains. The increased peak capacity, sensitivity and selectivity afforded by GC×GC–TOFMS allowed peak co-elutions, chromatographic artefacts, and dynamic range to be more easily addressed and managed. Furthermore, the software associated with GC×GC–TOFMS provided several additional benefits including improved peak alignment between samples and increased consistency of reported results, overall allowing for additional statistical tests to be applied following data processing. Future GC–qMS results could be improved by implementing some of these software-associated procedures, potentially reducing the magnitude of variation observed between GC–qMS and GC×GC–TOFMS studies. One-dimensional GC analysis may also benefit substantially from coupling with TOFMS detection to provide an indirect increase in peak capacity using deconvolution. However, the wealth of information gained by using GC×GC–TOFMS in decomposition odour profiling is undoubtedly an asset in this field of research.
Stadler, S, Desaulniers, J-P & Forbes, SL 2015, 'Inter-year repeatability study of volatile organic compounds from surface decomposition of human analogues', INTERNATIONAL JOURNAL OF LEGAL MEDICINE, vol. 129, no. 3, pp. 641-650.View/Download from: Publisher's site
Security control is becoming a major global issue in strategic locations, such as airports, official buildings, and transit stations. The agencies responsible for public security need powerful and sensitive tools to detect warfare agents and explosives. Volatile signature detection is one of the fastest and easiest ways to achieve this task. However, explosive chemicals have low volatility making their detection challenging. In this research, we developed and evaluated fast chromatographic methods to improve the characterization of volatile signatures from explosives samples. The headspace of explosives was sampled with solid phase micro-extraction fiber (SPME). Following this step, classical gas chromatography (GC) and comprehensive two-dimensional GC (GC×GC) were used for analysis. A fast GC approach allows the elution temperature of each analyte to be decreased, resulting in decreased thermal degradation of sensitive compounds (e.g., nitro explosives). Using fast GC×GC, the limit of detection is further decreased based on the cryo-focusing effect of the modulator. Sampling of explosives and chromatographic separation were optimized, and the methods then applied to commercial explosives samples. Implementation of fast GC methods will be valuable in the future for defense and security forensics applications.
Stefanuto, P-H, Perrault, KA, Stadler, S, Pesesse, R, LeBlanc, HN, Forbes, SL & Focant, J-F 2015, 'GC x GC-TOFMS and supervised multivariate approaches to study human cadaveric decomposition olfactive signatures', ANALYTICAL AND BIOANALYTICAL CHEMISTRY, vol. 407, no. 16, pp. 4767-4778.View/Download from: Publisher's site
Perrault, KA, Stefanuto, P-H, Stuart, BH, Rai, T, Focant, J-F & Forbes, SL 2015, 'Reducing variation in decomposition odour profiling using comprehensive two-dimensional gas chromatography', Journal of Separation Science, vol. 38, no. 1, pp. NA-NA.View/Download from: Publisher's site
Ueland, M, Nizio, KD, Forbes, SL & Stuart, BH 2015, 'The interactive effect of the degradation of cotton clothing and decomposition fluid production associated with decaying remains', Forensic Science International, vol. 255, pp. 56-63.View/Download from: Publisher's site
Abstract Textiles are a commonly encountered source of evidence in forensic cases. In the past, most research has been focused on how textiles affect the decomposition process while little attention has been paid to how the decomposition products interact with the textiles. While some studies have shown that the presence of remains will have an effect on the degradation of clothing associated with a decaying body, very little work has been carried out on the specific mechanisms that prevent or delay textile degradation when in contact with decomposing remains. In order to investigate the effect of decomposition fluid on textile degradation, three clothed domestic pig (Sus scrofa domesticus) carcasses were placed on a soil surface, textile specimens were collected over a period of a year and were then analysed using ATR-FTIR spectroscopy and GC-MS. Multivariate statistical analysis was used to analyse the data. Cotton specimens not associated with remains degraded markedly, whereas the samples exposed to decomposition fluids remained relatively intact over the same time frame. An investigation of the decomposition by-products found that the protein-related bands remained stable and unchanged throughout the experiment. Lipid components, on the other hand, demonstrated a significant change; this was confirmed with the use of both ATR-FTIR spectroscopy and GC-MS. Through an advanced statistical approach, information about the decomposition by-products and their characteristics was obtained. There is potential that the lipid profile in a textile specimen could be a valuable tool used in the examination of clothing located at a crime scene.
Buis, R, Rust, L, Nizio, K, Rai, T, Stuart, B & Forbes, S 2015, 'Investigating the Sensitivity of Cadaver-Detection Dogs to Decomposition Fluid', Journal of Forensic Identification, vol. 65, no. 6, pp. 985-997.
Cadaver-detection dogs are regularly used by police and emergency services to locate human remains. Because of ethical restrictions, the dogs are not trained using cadavers, but instead, on pseudo-scents or human tissues, such as blood, bone, and decomposition fluid. However, the accuracy of these training aids as substitutes for human remains is unknown. The aim of this study was to investigate the dogs' sensitivity to human decomposition fluid as a training aid and to determine whether their sensitivity increased with exposure.
Perrault, KA, Rai, T, Stuart, BH & Forbes, SL 2015, 'Seasonal comparison of carrion volatiles in decomposition soil using comprehensive two-dimensional gas chromatography - time of flight mass spectrometry', ANALYTICAL METHODS, vol. 7, no. 2, pp. 690-698.View/Download from: Publisher's site
Perrault, KA, Stefanuto, P-H, Stuart, BH, Rai, T, Focant, J-F & Forbes, SL 2015, 'Detection of decomposition volatile organic compounds in soil following removal of remains from a surface deposition site', FORENSIC SCIENCE MEDICINE AND PATHOLOGY, vol. 11, no. 3, pp. 376-387.View/Download from: Publisher's site
Perrault, KA, Stefanuto, P-H, Stuart, BH, Rai, T, Focant, J-F & Forbes, SL 2015, 'Reducing variation in decomposition odour profiling using comprehensive two-dimensional gas chromatography.', Journal of Separation Science, vol. 38, no. 1, pp. 73-80.View/Download from: Publisher's site
Challenges in decomposition odour profiling have led to variation in the documented odour profile by different research groups worldwide. Background subtraction and use of controls are important considerations given the variation introduced by decomposition studies conducted in different geographical environments. The collection of volatile organic compounds (VOCs) from soil beneath decomposing remains is challenging due to the high levels of inherent soil VOCs, further confounded by the use of highly sensitive instrumentation. This study presents a method that provides suitable chromatographic resolution for profiling decomposition odour in soil by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry using appropriate controls and field blanks. Logarithmic transformation and t-testing of compounds permitted the generation of a compound list of decomposition VOCs in soil. Principal component analysis demonstrated the improved discrimination between experimental and control soil, verifying the value of the data handling method. Data handling procedures have not been well documented in this field and standardisation would thereby reduce misidentification of VOCs present in the surrounding environment as decomposition byproducts. Uniformity of data handling and instrumental procedures will reduce analytical variation, increasing confidence in the future when investigating the effect of taphonomic variables on the decomposition VOC profile.
Stefanuto, P-H, Perrault, KA, Lloyd, RM, Stuart, B, Rai, T, Forbes, SL & Focant, J-F 2015, 'Exploring new dimensions in cadaveric decomposition odour analysis', Anal. Methods.View/Download from: Publisher's site
Chemical profiling of decomposition odour is conducted in the environmental sciences to detect malodourous target sources in air, water or soil. More recently decomposition odour profiling has been employed in the forensic sciences to generate a profile of the volatile organic compounds (VOCs) produced by decomposed remains. The chemical profile of decomposition odour is still being debated with variations in the VOC profile attributed to the sample collection technique, method of chemical analysis, and environment in which decomposition occurred. To date, little consideration has been given to the partitioning of odour between different matrices and the impact this has on developing an accurate VOC profile. The purpose of this research was to investigate the decomposition odour profile surrounding vertebrate carrion to determine how VOCs partition between soil and air. Four pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their odour profile monitored over a period of two months. Corresponding control sites were also monitored to determine the VOC profile of the surrounding environment. Samples were collected from the soil below and the air (headspace) above the decomposed remains using sorbent tubes and analysed using gas chromatography-mass spectrometry. A total of 249 compounds were identified but only 58 compounds were common to both air and soil samples. This study has demonstrated that soil and air samples produce distinct subsets of VOCs that contribute to the overall decomposition odour. Sample collection from only one matrix will reduce the likelihood of detecting the complete spectrum of VOCs, which further confounds the issue of determining a complete and accurate decomposition odour profile. Confirmation of this profile will enhance the performance of cadaver-detection dogs that are tasked with detecting decomposition odour in both soil and air to locate victim remains.
Forbes, SL, Perrault, KA, Stefanuto, P-H, Nizio, KD & Focant, J-F 2014, 'Comparison of the decomposition VOC profile during winter and summer in a moist, mid-latitude (Cfb) climate', PLoS ONE, vol. 9, no. 11, pp. 1-11.View/Download from: Publisher's site
The investigation of volatile organic compounds (VOCs) associated with decomposition is an emerging field in forensic taphonomy due to their importance in locating human remains using biological detectors such as insects and canines. A consistent decomposition VOC profile has not yet been elucidated due to the intrinsic impact of the environment on the decomposition process in different climatic zones. The study of decomposition VOCs has typically occurred during the warmer months to enable chemical profiling of all decomposition stages. The present study investigated the decomposition VOC profile in air during both warmer and cooler months in a moist, mid-latitude (Cfb) climate as decomposition occurs year-round in this environment. Pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their VOC profile was monitored during the winter and summer months. Corresponding control sites were also monitored to determine the natural VOC profile of the surrounding soil and vegetation. VOC samples were collected onto sorbent tubes and analyzed using comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GC×GC-TOFMS). The summer months were characterized by higher temperatures and solar radiation, greater rainfall accumulation, and comparable humidity when compared to the winter months. The rate of decomposition was faster and the number and abundance of VOCs was proportionally higher in summer. However, a similar trend was observed in winter and summer demonstrating a rapid increase in VOC abundance during active decay with a second increase in abundance occurring later in the decomposition process. Sulfur-containing compounds, alcohols and ketones represented the most abundant classes of compounds in both seasons, although almost all 10 compound classes identified contributed to discriminating the stages of decomposition throughout both seasons. The advantages of GC×GC-TOFMS were demonstrated for d...
Ruffell, A, Pringle, JK & Forbes, SL 2014, 'Search protocols for hidden forensic objects beneath floors and within walls', Forensic Science International, vol. 237, pp. 137-145.View/Download from: Publisher's site
The burial of objects (human remains, explosives, weapons) below or behind concrete, brick, plaster or tiling may be associated with serious crime and are difficult locations to search. These are quite common forensic search scenarios but little has been published on them to-date. Most documented discoveries are accidental or from suspect/witness testimony. The problem in locating such hidden objects means a random or chance-based approach is not advisable. A preliminary strategy is presented here, based on previous studies, augmented by primary research where new technology or applications are required. This blend allows a rudimentary search workflow, from remote desktop study, to non-destructive investigation through to recommendations as to how the above may inform excavation, demonstrated here with a case study from a homicide investigation. Published case studies on the search for human remains demonstrate the problems encountered when trying to find and recover sealed-in and sealed-over locations. Established methods include desktop study, photography, geophysics and search dogs: these are integrated with new technology (LiDAR and laser scanning; photographic rectification; close-quarter aerial imagery; ground-penetrating radar on walls and gamma-ray/neutron activation radiography) to propose this possible search strategy.
Rust, L, Forbes, SL, Trebilcock, K, Perrault, KA & McGrath, LT 2014, 'Effect of age and storage conditions on the volatile organic compound profile of blood', Forensic Science, Medicine, and Pathology, vol. 10, no. 4, pp. 570-582.View/Download from: Publisher's site
Stefanuto, P-H, Perrault, K, Stadler, S, Pesesse, R, Brokl, M, Forbes, S & Focant, J-F 2014, 'Reading Cadaveric Decomposition Chemistry with a New Pair of Glasses', ChemPlusChem, vol. 79, no. 6, pp. 786-789.View/Download from: Publisher's site
Ueland, M, Breton, H & Forbes, SL 2014, 'Bacterial populations associated with early-stage adipocere formation in lacustrine waters', International Journal of Legal Medicine, vol. 128, no. 2, pp. 379-387.View/Download from: Publisher's site
The preservation of soft tissue is a valuable evidence for forensic investigation as it may provide information about the cause and manner of death as well as the time since death. Adipocere forms from the conversion of triglycerides in the neutral fats into stable fatty acids producing a solid white product which aids tissue preservation. Adipocere will typically form in water-logged grave sites and aquatic environments. Documentation on the chemical and microbiological changes that cause adipocere formation in aquatic environments is scant and mostly based on observational case reports. The aim of this study was to monitor the early adipocere formation in lacustrine waters to investigate the effect of aquatic bacteria on adipocere formation. Tissue samples from pork (Sus scrofa domesticus) belly were submerged in water samples from Lake Ontario and deionised water (control). Bacteria samples from both water and tissue were harvested. Changes in the fatty acid composition of the tissue were determined using gas chromatography-mass spectrometry. Early-stage adipocere formation was confirmed on porcine tissue submerged in lake water but was not identified on porcine tissue submerged in deionised water. Adipocere formation required an abundance of gram-positive bacteria during the early postmortem period to assist in lipolysing the triglycerides into free fatty acids. Formation of adipocere in the lake water resulted in a decrease in bacterial concentrations in the tissue over time.
Focant, J, Stefanuto, P, Brasseur, C, Dekeirsschieter, J, Haubruge, E, Schotsmans, E, Wilson, A, Stadler, S & Forbes, SL 2013, 'Forensic cadaveric decomposition profiling by GCxGC-TOFMS analysis of VOCs', Chemical Bulletin of Kazakh National University, vol. 4, no. 72, pp. 177-186.View/Download from: Publisher's site
Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) has been used to analyze complex mixtures of volatile organic compounds (VOCs) produced during cadaveric decomposition processes. The use of specific mass spectrometric scripting approaches permitted to easily identify gravesoils from control soils. The high peak capacity of the system, as well as the development of a specific data processing approach allowed the isolation and identification of several hundreds of specific analytes. When coupled to thermal desorption (TD), GC×GC-TOFMS is the tool of choice for cadaveric VOC profiling.
Forbes, SL, Hulsman, S & Dolderman, M 2013, 'Locating buried canine remains using ground penetrating radar', Canadian Society of Forensic Science Journal, vol. 46, no. 1, pp. 51-58.View/Download from: Publisher's site
Ground penetrating radar (GPR) is a valuable geophysical tool to assist in the search for buried targets, including clandestine graves. Its use in forensic investigations has been limited due to a misconception of its capabilities and a lack of understanding of the limitations associated with its use. This case report details the application of GPR for locating buried canine remains at the request of the Ontario Provincial Police (OPP) in Canada. The canine was a police dog killed in the line of duty in 1975. His remains had been buried in a casket with concrete poured over the top prior to burial, however the exact location of the burial site was unknown. A Sensors and Software Smart Cart 500 MHz GPR system was used to locate the grave site on the front lawn of the OPP North Bay Detachment. The GPR data was collected in an X-Y grid format and analysed using Sensors and Software Ekko Mapper 4. This program allows the plots to be viewed from a bird's eye view as depth slices rather than cross sections of the soil. Identification of the grave site allowed for the canine's remains to be exhumed, cremated, and subsequently relocated to the OPP Museum in Orillia.
Larizza, M & Forbes, SL 2013, 'Detection of fatty acids in the lateral extent of the cadaver decomposition island', Geological Society, London, vol. 384, pp. 209-219.View/Download from: Publisher's site
Identifying biomarkers of decomposition may prove to be an important area of environmental and criminal forensics research. Biomarkers released during the decomposition process can be detected in soil as a means of confirming the presence of a decomposition site in the case of relocated or scavenged remains. This study was conducted to characterize the fatty acid profile in soil containing decomposition fluid and to determine the lateral extent of fatty acid release in the cadaver decomposition island (CDI). Owing to practical and ethical restrictions, the study utilized pig carcasses as human analogues to investigate postmortem decomposition on a soil surface. Soil samples were collected from directly beneath the carcasses and at increasing distances from the carcasses within the CDI. Fatty acids were extracted with chloroform, derivatized with a silylating agent and analysed using gas chromatographymass spectrometry (GC-MS). Saturated and unsaturated fatty acids were detected including myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0) and oleic (C18:1) acids. Fatty acids were detected up to 50 cm in the lateral extent of the CDI at significantly higher levels in decomposition soil than in the control soil. The results indicate that fatty acid analysis of decomposition soil could be used to confirm the location of a decomposition site.
Lowe, A, Beresford, D, Carter, DO, Gaspari, F, O'Brien, RC & Forbes, SL 2013, 'Ground penetrating radar use in three contrasting soil textures in southern Ontario', Geological Society, London, vol. 384, pp. 221-228.View/Download from: Publisher's site
Ground penetrating radar (GPR) is a non-invasive, geophysical tool that can be used for the identification of clandestine graves. GPR operates by detecting density differences in soil by the transmission of high frequency electromagnetic waves from an antenna. Domestic pig (Sus scrofa domesticus) carcasses were clothed in 100% cotton t-shirts and 50% cotton/50% polyester briefs, and buried at a consistent depth at three field sites of contrasting soil texture (silty clay loam, fine sand and fine sandy loam) in southern Ontario. GPR was used to detect and monitor the graves for a period of 14 months post-burial. Analysis of collected data revealed that GPR had applicability in the identification of clandestine graves in silty clay loam and fine sandy loam soils, but was not suitable for detection in the fine sandy soil studied. The results of this research have applicability within forensic investigations involving decomposing remains by aiding in the location of clandestine graves in loam soils in southern Ontario through the use of GPR.
Pahor, K, Olson, G & Forbes, SL 2013, 'Postmortem detection of gasoline residues in lung tissue and heart blood of fire victims', International Journal of Legal Medicine, vol. 127, no. 5, pp. 923-930.View/Download from: Publisher's site
The purpose of this study was to determine whether gasoline residues could be detected post-mortem in lung tissue and heart blood of fire victims. The lungs and heart blood were investigated to determine whether they were suitable samples for collection and could be collected without contamination during an autopsy. Three sets of test subjects (pig carcasses) were investigated under two different fire scenarios. Test subjects 1 were anaesthetized following animal ethics approval, inhaled gasoline vapours for a short period and then euthanized. The carcasses were clothed and placed in a house where additional gasoline was poured onto the carcass post-mortem in one fire, but not in the other. Test subjects 2 did not inhale gasoline, were clothed and placed in the house and had gasoline poured onto them in both fires. Test subjects 3 were clothed but had no exposure to gasoline either ante- or post-mortem. Following controlled burns and suppression with water, the carcasses were collected, and their lungs and heart blood were excised at a necropsy. The headspace from the samples was analysed using thermal desorption-gas chromatography-mass spectroscopy. Gasoline was identified in the lungs and heart blood from the subjects that were exposed to gasoline vapours prior to death (test subjects 1). All other samples were negative for gasoline residues. These results suggest that it is useful to analyse for volatile ignitable liquids in lung tissue and blood as it may help to determine whether a victim was alive and inhaling gases at the time of a fire.
Stadler, S, Stefanuto, P, Brokl, M, Forbes, SL & Focant, J 2013, 'Characterization of volatile organic compounds from human analogue decomposition using thermal desorption coupled to comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry', Analytical Chemistry, vol. 85, no. 2, pp. 998-1005.View/Download from: Publisher's site
Complex processes of decomposition produce a variety of chemicals as soft tissues, and their component parts are broken down. Among others, these decomposition byproducts include volatile organic compounds (VOCs) responsible for the odor of decomposition. Human remains detection (HRD) canines utilize this odor signature to locate human remains during police investigations and recovery missions in the event of a mass disaster. Currently, it is unknown what compounds or combinations of compounds are recognized by the HRD canines. Furthermore, a comprehensive decomposition VOC profile remains elusive. This is likely due to difficulties associated with the nontarget analysis of complex samples. In this study, cadaveric VOCs were collected from the decomposition headspace of pig carcasses and were further analyzed using thermal desorption coupled to comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (TD-GC × GC-TOFMS). Along with an advanced data handling methodology, this approach allowed for enhanced characterization of these complex samples. The additional peak capacity of GC × GC, the spectral deconvolution algorithms applied to unskewed mass spectral data, and the use of a robust data mining strategy generated a characteristic profile of decomposition VOCs across the various stages of soft-tissue decomposition. The profile was comprised of numerous chemical families, particularly alcohols, carboxylic acids, aromatics, and sulfides. Characteristic compounds identified in this study, e.g., 1-butanol, 1-octen-3-ol, 2-and 3-methyl butanoic acid, hexanoic acid, octanal, indole, phenol, benzaldehyde, dimethyl disulfide, and trisulfide, are potential target compounds of decomposition odor. This approach will facilitate the comparison of complex odor profiles and produce a comprehensive VOC profile for decomposition.
Stokes, KL, Forbes, SL & Tibbett, M 2013, 'Human versus animal: contrasting decomposition dynamics of mammalian analogues in experimental taphonomy', Journal of Forensic Sciences, vol. 58, no. 3, pp. 583-591.View/Download from: Publisher's site
Taphonomic studies regularly employ animal analogues for human decomposition due to ethical restrictions relating to the use of human tissue. However, the validity of using animal analogues in soil decomposition studies is still questioned. This study compared the decomposition of skeletal muscle tissues (SMTs) from human (Homo sapiens), pork (Sus scrofa), beef (Bos taurus), and lamb (Ovis aries) interred in soil microcosms. Fixed interval samples were collected from the SMT for microbial activity and mass tissue loss determination; samples were also taken from the underlying soil for pH, electrical conductivity, and nutrient (potassium, phosphate, ammonium, and nitrate) analysis. The overall patterns of nutrient fluxes and chemical changes in nonhuman SMT and the underlying soil followed that of human SMT. Ovine tissue was the most similar to human tissue in many of the measured parameters. Although no single analogue was a precise predictor of human decomposition in soil, all models offered close approximations in decomposition dynamics.
Von Der Luhe, B, Dawson, L, Fiedler, SL, Mayes, R & Forbes, SL 2013, 'Investigation of sterols as potential biomarkers for the detection of pig (S. s. domesticus) decomposition fluid in soils', Forensic Science International, vol. 230, no. 1-3, pp. 68-73.View/Download from: Publisher's site
This study was carried out to evaluate the potential of using cholesterol and coprostanol, as indicators for the detection of decomposition fluid of buried pigs (S. s. domesticus) in soils. In May 2007, four pig carcasses (~35 kg) were buried in shallow graves (~40 cm depth) at the University of Ontario Institute of Technology in Canada. Two pigs were exhumed after three months (Pig 1, Pig 2) and six months (Pig 3, Pig 4) post burial. Soil samples were collected beneath the pig carcasses (~40 cm depth) and from grave walls (~1520 cm depth) as well as from a parallel control site. Coprostanol and cholesterol were extracted from soils, purified with solid phase extraction (SPE) and analysed with gas chromatography/mass spectrometry (GC/MS). A significant increase in cholesterol concentrations (p < 0.05) and amounts of coprostanol were detected in soil located beneath the pig carcasses after three months of burial. It is assumed that during the putrefaction and liquefaction stages of decomposition pig fluid which contains cholesterol and coprostanol is released into the underlying soil. Therefore, cholesterol and coprostanol could be used as potential biomarkers to detect the presence of decomposition fluid three months after burial under comparable soil and environmental conditions. Further research is suggested for additional soil sampling before and after three months to investigate the abundance of these and other sterols.
Lowe, A, Beresford, D, Carter, DO, Gaspari, F, O'Brien, RC, Stuart, BH & Forbes, SL 2013, 'The effect of soil texture on the degradation of textiles associated with buried bodies', Forensic Science International, vol. 231, pp. 331-339.View/Download from: Publisher's site
There are many factors which affect the rate of decomposition in a grave site including; the depth of burial, climatic conditions, physical conditions of the soil (e.g. texture, pH, moisture), and method of burial (e.g. clothing, wrappings). Clothing is often studied as a factor that can slow the rate of soft tissue decomposition. In contrast, the effect of soft tissue decomposition on the rate of textile degradation is usually reported as anecdotal evidence rather than being studied under controlled conditions. The majority of studies in this area have focused on the degradation of textiles buried directly in soil. The purpose of this study was to investigate the effect of soil texture on the degradation and/or preservation of textile materials associated with buried bodies. The study involved the burial of clothed domestic pig carcasses and control clothing in contrasting soil textures (silty clay loam, fine sand and fine sandy loam) at three field sites in southern Ontario, Canada. Graves were exhumed after 2, 12 and 14 months burial to observe the degree of degradation for both natural and synthetic textiles. Recovered textile samples were chemically analyzed using infrared (IR) spectroscopy and gas chromatographymass spectrometry (GCMS) to investigate the lipid decomposition by-products retained in the textiles. The findings of this study demonstrate that natural textile in contact with a buried decomposing body will be preserved for longer periods of time when compared to the same textile buried directly in soil and not in contact with a body. The soil texture did not visually impact the degree of degradation or preservation. Furthermore, the natural-synthetic textile blend was resistant to degradation, regardless of soil texture, contact with the body or time since deposition. Chemical analysis of the textiles using GCMS correctly identified a lipid degradation profile consistent with the degree of soft tissue decomposition
Stadler, S, Stefanuto, P, Byer, JD, Brokl, M, Forbes, SL & Focant, J 2012, 'Analysis of synthetic canine training aids by comprehensive two-dimensional gas chromatography-time of flight mass spectrometry', Journal Of Chromatography A, vol. 1255, pp. 202-206.View/Download from: Publisher's site
Cadaver dogs are trained on a variety of materials, including artificial or pseudo scents. The chemical components of commercially available pseudo scents are not known, so their accuracy as a decomposition odour mimic and their effectiveness as a canine training aid have not been evaluated. Two pseudo scents that are commercially available and used for training cadaver dogs were analysed using comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (GC x GC-TOFMS). The two formulations were determined to be simplistic in their composition, compared to real cadaveric volatile organic compound (VOC) mixtures, with only a few major components. The enhanced GC x GC-TOFMS peak capacity was nevertheless useful to discriminate less intense peaks from large overloaded peaks. The availability of both dimension retention times combined with the peak finding and deconvolution algorithm, enabled the chemical characterization of the two formulations. Additionally, high resolution (HR) TOFMS was used to extract molecular formulae and confirm identities of analytes. The seven compounds identified by this work have not been reported previously as volatile products of decomposition, indicating that these pseudo scents are not to be considered as an accurate representation of cadaveric decomposition odour. Further research on the olfaction of scent detection canines and the chemical composition of their target odourants needs to be conducted to develop improved canine training aids.
Cassar, J, Stuart, BH, Dent, BB, Notter, SJ, Forbes, SL, O'Brien, C & Dadour, IR 2011, 'A study of adipocere in soil collected from a field leaching study', Australian Journal of Forensic Sciences, vol. 43, no. 1, pp. 3-11.View/Download from: Publisher's site
An investigation of a post-mortem product, adipocere, resulting from the decomposition of a pig carcass left on a soil surface is reported. The presence of this material should provide valuable information for forensic investigators: although a body may have been removed from a crime scene, decomposition products may remain in the soil below and the depth to which these are observed can provide insight into the problem of how long a body remained on the soil surface. Infrared spectroscopy and gas chromatographymass spectrometry were used in this study to identify the compounds associated with adipocere, which is comprised of particular fatty acids, in soil samples taken from different depths below the carcass. Both techniques demonstrate that adipocere may be detected in soil beneath a body and the depth to which it is detected is dependent upon the time since the body was deposited on the soil surface.
Forbes, SL, Wilson, MA & Stuart, BH 2011, 'Examination of adipocere formation in a cold water environment', International Journal of Legal Medicine, vol. 125, no. 5, pp. 643-650.View/Download from: Publisher's site
Adipocere is a late-stage postmortem decomposition product that forms from the lipids present in soft tissue. Its formation in aquatic environments is typically related to the presence of a moist, warm, anaerobic environment, and the effect of decomposer
Bissonnette, M, Knaap, W & Forbes, SL 2010, 'Steam development of latent fingerprints on thermal paper', Journal of Forensic Identification, vol. 60, no. 6, pp. 619-638.
The purpose of this study was to use a novel steam technique to develop latent fingerprints on thermal paper. Several factors were investigated including the mechanism of reaction, the effect of time since fingerprint deposition, and the ability to develop fingerprints on thermal paper obtained from a variety of sources. The mechanism of the reaction was found to be a reaction with unsaturated lipids from sebaceous secretions such as unsaturated fatty acids and squalene. The steam technique was effective at developing fingerprints up to four weeks since deposition. Steam developed identifiable fingerprints on a wide variety of thermal paper, with a success rate of 41% overall. These results are comparable to other techniques used in law enforcement today. It was concluded that the steam technique is a viable method for developing latent fingerprints on thermal paper.
Comstock, J, Beeton, M & Forbes, SL 2010, 'An investigation of barefoot morphology, friction ridges and their significance in forensic identification', Identification Canada, vol. 33, pp. 4-19.
O'Brien, RC, Forbes, SL, Meyer, J & Dadour, I 2010, 'Forensically significant scavenging guilds in the southwest of Western Australia', Forensic Science International, vol. 198, no. 1-3, pp. 85-91.View/Download from: Publisher's site
Estimation of time since death is an important factor in forensic investigations and the state of decomposition of a body is a prime basis for such estimations. The rate of decomposition is, however, affected by many environmental factors such as tempera
O'Brien, RC, Larcombe, A, Meyer, J, Forbes, SL & Dadour, I 2010, 'The scavenging behaviour of the Australian Raven (Corvus coronoides): patterns and influencing factors', Sylvia, vol. 46, pp. 133-148.
The Australian Raven (Corvus coronoides) is a widespread, abundant corvid which is often considered a pest species, due to the thought that it predates on livestock, ruin crops, and is often seen feeding on refuse, in both urban and rural areas. The species is known to feed on a range of material from seeds in ploughed fields to human refuse and decomposing organic material. A large proportion of its diet consists of carrion, and as such, the Australian Raven is an effective detrivorous species capable of removing and consuming dead and decomposing carcasses. This research examined the scavenging pattern of the Australian Raven on domestic pig (Sus scrofa) carcasses at four different locations surrounding Perth, Western Australia. Domestic pig carcasses were sacrificed and placed in outdoor environments and the carcasses were filmed using infrared cameras with time-lapse image capture. The number of feeding events, length of feeding, material being fed upon, and associated weather data were recorded. Furthermore, the influences of location, season and life cycle of the Australian Raven on scavenging behaviour is examined. It was found that raven scavenging intensity was greatest during spring and as an omnivore there was significantly higher feeding on both flesh and insects in one event than either material on its own.
Swann, L, Chidlow, GE, Forbes, SL & Lewis, SW 2010, 'Preliminary studies into the characterization of chemical markers of decomposition for geoforensics', Journal Of Forensic Sciences, vol. 55, no. 2, pp. 308-314.View/Download from: Publisher's site
In this paper, we report the results of our preliminary studies into chemical characterization of the fluids produced during decomposition in the absence of a soil matrix. Pig (Sus domestica) carcasses were used to model the human decomposition process i
Swann, L, Forbes, SL & Lewis, SW 2010, 'Observations of the temporal variation in chemical content of decomposition fluid: A preliminary study using pigs as a model system', Australian Journal of Forensic Sciences, vol. 42, no. 3, pp. 199-210.View/Download from: Publisher's site
In this paper we report the results of our preliminary studies into short chain fatty acids that have the potential to show reproducible patterns over certain postmortem intervals during decomposition in the absence of a soil matrix. Additional compounds
Swann, LM, Forbes, SL & Lewis, SW 2010, 'A capillary electrophoresis method for the determination of selected biogenic amines and amino acids in mammalian decomposition fluid', Talanta, vol. 81, pp. 1697-1702.View/Download from: Publisher's site
A simple capillary zone electrophoresis method for the determination of selected biogenic amines (tyramine and tryptamine) and amino acids (tryptophan, phenylalanine and tyrosine) in mammalian decomposition fluids is presented Separations were carried out in a fused silica capillary (75 mu m i d, total length 65 cm. effective length 56 cm) with detection by ultraviolet absorbance spectrophotometry at 200 nm. In order to improve resolution and total analysis time, the method was subjected to optimisation utilising a chemometric approach. A screening design was carried out followed by a central composite design (CCD), using peak resolution and total analysis time as response factors The influences of four experimental variables (pH. background electrolyte concentration, percentage of organic modifier (methanol) and applied voltage) were investigated. Optimum separation conditions were determined to be: a background electrolyte of boric acid (70 mM) adjusted to pH 9.5 with 0 1 M sodium hydroxide with 32% methanol (v/v). Applied voltage was 30 kV. with the resulting current being less than 26 mu A Under these conditions the analytes were separated within 12 min. Tryptamine, tyramine, tryptophan, tyrosine and phenylalanine were identified by migration time and spiking in porcine decomposition fluids.
Swann, LM, Forbes, SL & Lewis, SW 2010, 'Analytical separations of mammalian decomposition products for forensic science: A review', Analytica Chimica Acta, vol. 682, pp. 9-22.View/Download from: Publisher's site
The study of mammalian soft tissue decomposition is an emerging area in forensic science with a major focus of the research being the use of various chemical and biological methods to study the fate of human remains in the environment Decomposition of mammalian soft tissue is a postmortem process that depending on environmental conditions and physiological factors will proceed until complete disintegration of the tissue The major stages of decomposition Involve complex reactions which result in the chemical breakdown of the body s main constituents lipids proteins and carbohydrates The first step to understanding this chemistry is identifying the compounds present in decomposition fluids and determining when they are produced This paper provides an overview of decomposition chemistry and reviews recent advances in this area utilising analytical separation science
Stokes, KL, Forbes, SL & Tibbett, M 2009, 'Freezing skeletal muscle tissue does not affect its decomposition in soil: Evidence from temporal changes in tissue mass, microbial activity and soil chemistry based on excised samples', Forensic Science International, vol. 183, no. 1-3, pp. 6-13.View/Download from: Publisher's site
The study of decaying organisms and death assemblages is referred to as forensic taphonomy, or more simply the study of graves. This field is dominated by the fields of entomology, anthropology and archaeology. Forensic taphonomy also includes the study
Van Belle, LE, Carter, DO & Forbes, SL 2009, 'Measurement of ninhydrin reactive nitrogen influx into gravesoil during aboveground and belowground carcass (Sus domesticus) decomposition', Forensic Science International, vol. 193, no. 1-3, pp. 37-41.View/Download from: Publisher's site
Carcass decomposition results in the release of nitrogenous compounds into associated soil. The current study investigated the release of ninhydrin reactive nitrogen (NRN) following burial (similar to 40 cm depth) and decomposition on the soil surface. A
Benninger, LA, Carter, DO & Forbes, SL 2008, 'The biochemical alteration of soil beneath a decomposing carcass', Forensic Science International, vol. 180, no. 2-3, pp. 70-75.View/Download from: Publisher's site
The processes associated with cadaver decomposition in outdoor settings, particularly those that occur during the extended Postmortem interval (>30 days) are poorly understood. Thus, few methods are currently available to accurately estimate the extended
Voss, SC, Forbes, SL & Dadour, IR 2008, 'Decomposition and insect succession on cadavers inside a vehicle environment', Forensic Science, Medicine, and Pathology, vol. 4, no. 1, pp. 22-32.View/Download from: Publisher's site
This study presents differences in rate of decomposition and insect succession between exposed carcasses on the soil surface and those enclosed within a vehicle following carbon monoxide (CO) poisoning. This study provides baseline data outlining the decomposition patterns of a carcass enclosed within a vehicle following CO poisoning in Western Australia. Understanding how variations in decomposition situations impact on the rate of decomposition and patterns of insect succession is essential to obtaining an accurate estimate of minimum post-mortem interval (PMI).
Watson, CJ & Forbes, SL 2008, 'An investigation of the vegetation associated with grave sites in southern Ontario', Canadian Society of Forensic Science Journal, vol. 41, pp. 199-207.
Botanical evidence may be used in forensic investigations to estimate postmortem interval (PMI) of decomposed remains, to link a suspect to a crime scene, and to track distribution of plant-based illicit substances. A recent application of botanical evidence to forensic science is for the potential identification of clandestine grave locations. The burial of pig carcasses for a decomposition study in southern Ontario provided the opportunity to investigate the botanical species associated with grave sites in this region. This study investigated the differences in vegetation structure and species composition on grave sites in an environment that was dominated by weed flora. Differences in botanical species between grave sites and undisturbed areas were identified and highlighted the potential of these species to be used as grave indicators. Further studies are recommended to investigate the effect of seasonal variation, land use type, and inter- and intra-year variations.
Onishi, A, Thomas, P, Stuart, BH, Guerbois, JL & Forbes, SL 2008, 'TG-MS analysis of the thermal decomposition of pig bone for forensic applications', Journal Of Thermal Analysis And Calorimetry, vol. 92, no. 1, pp. 87-90.View/Download from: Publisher's site
In order to investigate the potential of thermal analysis for the determination of post-mortem age, rib bone specimens were collected from the remains of a number of slaughtered pigs that were allowed to decompose in the Australian bush in a controlled site under a range of conditions for time periods ranging from 1 to 5 years. The bone specimens were cut in cross-section with the compact bone collected for analysis. TG-MS curves were collected by heating bone samples to 1100°C in an argon atmosphere. The TG-MS data showed significant differences for the pig bone specimens derived from the different environments and showed trends in peak size correlating with age. The reported data suggest that TG-MS has significant potential for the identification of origin as well as the ageing of skeletal remains in a forensic context.
O'Brien, RC, Forbes, SL, Meyer, J & Dadour, IR 2007, 'A preliminary investigation into the scavenging activity on pig carcasses in Western Australia', Forensic Science, Medicine, and Pathology, vol. 3, no. 3, pp. 194-199.
Human remains exposed to an outdoor environment are subject not only to the process of decomposition, but also to the activity of scavenging fauna. The scavenging behavior of fauna can vary considerably with region and season, affecting the rate of decomposition, and more importantly, the accuracy of postmortem interval estimations. A thorough knowledge of the scavenging behavior of fauna present in the local environment is imperative for law enforcement and forensic investigators dealing with decomposed remains located outdoors. This study was conducted to identify the major scavengers of decomposing remains in the southwest region of Western Australia. Avian species were identified as the dominant scavengers amongst a range of birds, reptiles, mammals, and amphibians feeding on cadaveric tissues and associated insects. The scavenging behavior of the fauna varied with seasonal factors, including temperature and rainfall. The preliminary results are useful for forensic investigations involving decomposed remains in the southwest region of Western Australia.
Onishi, A, Thomas, P, Stuart, BH, Guerbois, JL & Forbes, SL 2007, 'TG-MS characterisation of pig bone in an inert atmosphere', Journal Of Thermal Analysis And Calorimetry, vol. 88, no. 2, pp. 405-409.View/Download from: Publisher's site
A challenge for forensic examiners is the ageing and characterisation of bone fragments or decomposed skeletal remains. Due to the sensitivity of thermal methods to morphological states, thermal analysis has been selected as a technique which could overcome the difficulties. In this preliminary study, TG-MS was applied to the characterisation of bone fragments derived from the compact bone of pig rib specimens. TG-MS curves were collected by heating bone samples to 1000 degrees C in an argon atmosphere. under these conditions, both the organic and inorganic phases decomposed, producing a variety of organic fragments and carbon dioxide. Pyrolysis of the organic phase, which is composed predominantly of collagen, occurred resulting in the observation of ion fragments up to 110 amu. Selected fragments were monited and their observation is discussed in terms of the decomposition of both the collagen phase and the inorganic carbonated hydroxyapatite phase.
Adipocere refers to a postmortem product which forms from body fat in the later stages of decomposition. Factors present in the surrounding decomposition environment will influence adipocere formation and may accelerate or retard the process of conversio
Adipocere is a decomposition product comprising predominantly of saturated fatty acids which results from the hydrolysis and hydrogenation of neutral fats in the body. Adipocere formation may occur in various decomposition environments but is chiefly dep
A controlled laboratory experiment was conducted in order to investigate the effect of the method of burial (i.e. the presence of coffin and clothing) on the formation of adipocere. This study follows previous studies by the authors who have investigated
Adipocere is a soft white substance formed postmortem from fatty tissue in a decomposing body. In this preliminary study the formation of adipocere in soil was investigated for a number of animal species. Adipocere was formed from the fatty tissue of pig
Attenuated total reflectance (ATR) infrared spectroscopy has been used to characterise pig adipocere formation. The composition of adipocere samples obtained by burial of pig adipocere tissue in soil and in mock coffins were compared with that of the original adipose tissue using this technique. The ATR spectra show that bands resulting from triglyceride and fatty acid C=O stretching are particularly useful fro monitoring the changes in adipocere formation. The technique is able to be used to investigate how the burial environment affects the rate of adipocere formation and supports the results of earlier gas chromatograph and mass spectrometer and diffuse reflectance infrared studies. ATR spectroscopy has also been demonsrtated to have the advantage of convenient sample reparation.
Forbes, SL 2004, 'Time since death: a novel approach to dating skeletal remains', Australian Journal of Forensic Sciences, vol. 36, no. 2, pp. 67-72.
Criminal investigators dealing with skeletal remains have the primary concern for determining whether the remains are of anthropological or archaeological interest. If the remains are determined to be from an anthropological era, the next concern becomes the determination of time since death (TSD). Despite advances in modern technology, TSD remains a most elusive determinant. It has critical value for providing police with a time frame in which the person may have gone missing, increasing the likelihood of a positive identification. This article outlines a novel approach to dating skeletal remains in an Australian context, but with global connotations
In-soil human decomposition is comprehensively described in terms of the physicochemical and bacterial environmental conditions. Much of the understanding comes from considerations of cemetery studies and experimentation with adipocere. The understandings are relevant for further studies in cemetery management, exhumations, forensic investigations and anthropology. In the soil, cadavers are subject to various sets of decomposition processes principally resulting from aerobic (usually the initial) or anaerobic (usually the sustaining) conditions. The presence of percolating groundwater and microorganisms further affects the rate of breakdown and fate of the products. The major human tissue components-protein, carbohydrate, fat and bone, are discussed; and the likely pathways of decomposition products enumerated. The effects of liquefaction, availability of oxygen and other in-grave processes are considered.
Adipocere is a postmortem decomposition porduct which forms from a body's adipose tissue. This study aimed to chemically demonstrate the process of conversion from adipose tissue to adipocere. Samples of adipocere were collected from pig cadavers that were allowed to decompose fro varying internals. Samples of soil were collected from beneath the cadavers and analused to determine the leaching effect of adipocere. Gas chromatography/mass spectrometry (GC/MS) was used to quantify the fatty acid composition of pig adipocere. Fourier transform infrared spectroscopy (FTIR) was used as a confirmatory test to identify other components such as triglycerides and aclcium salts of fatty acids. The study demonstrates the process of adipocere formation and the stages of formation through which the process passes using chemical techniques.
Forbes, SL, Keegan, J, Stuart, BH & Dent, BB 2003, 'A gas chromatography-mass spectrometry method for the detection of adipocere in grave soils', European Journal of Lipid Science and Technology, vol. 105, pp. 761-768.View/Download from: Publisher's site
Soil samples recovered from grave exhumations have been analysed in an attempt to identify and characterise adipocere contained in the samples. The soil samples were collected from different environments, including samples recovered from forensic grave sites. Gas chromatographymass spectrometry (GCMS) was employed to identify adipocere and characterise the fatty acid composition. X-ray diffraction was used to characterise the soil environments.
Soil samples recovered from grave exhumations have been analysed in an attempt to identify and characterise adipocere contained in the samples. The soil samples were collected from different environments, including samples recovered from forensic grave sites. Gas chromatography-mass spectrometry (GC-MS) was employed to identify adipocere and characterise the fatty acid composition. X-ray diffraction was used to characterise the soil environments.
Stuart, BH, Forbes, S, Dent, BB & Hodgson, G 2000, 'Studies of adipocere using diffuse reflectance infrared spectroscopy', VIBRATIONAL SPECTROSCOPY, vol. 24, no. 2, pp. 233-242.View/Download from: Publisher's site
Time since death (TSD) is defined as the time frame between death and discovery of an organism. When estimated in an archaeological context, this time frame may be referred to as time since deposition and in a forensic context can be termed postmortem interval. Time since death cannot be established with certainty and for this reason is provided as an estimate of the range of time encompassing the period when death occurred. A shorter postmortem interval is typically associated with a narrower time range, while a longer postmortem interval has a broader time range and includes a wider margin of error. Presently, there is no single indicator which provides a reliable or accurate measure of the time since death of an organism.
Breton, HA, Kirkwood, AE, Carter, DO & Forbes, SL 2016, 'Changes in Soil Microbial Activity Following Cadaver Decomposition During Spring and Summer Months in Southern Ontario' in Kars, H & Eijkel, LVD (eds), Soil in Criminal and Environmental Forensics. Soil Forensics, Springer, Germany, pp. 243-262.View/Download from: Publisher's site
Bodies are often disposed of clandestinely in environments allowing direct contact with soil yet the impact of cadaver decomposition on the surrounding environment remains generally poorly studied. The microbial load associated with a decomposing body is substantial and it is believed that decomposition has a notable impact on the surrounding soil microbiology. During 2011 and 2012 a study consisting of four experimental trials was undertaken at the University of Ontario Institute of Technology decomposition facility located in Southern Ontario. The study documented the decomposition of human analogues (pig carcasses) and the subsequent microbiological impacts on the soil within the decomposition islands created. Two trials were conducted per year, one in the spring and one in the summer to account for seasonal variations. For each trial, soil samples were collected from three experimental sites and three controls sites over a 3 month period. Sample analysis included soil pH, moisture and microbial activity using a fluorescein diacetate assay. Microbial activity levels between control and experimental samples were compared on each sampling day and overall for all trials. An increase in microbial activity was observed on multiple occasions during the Spring 2011, Summer 2011 and Spring 2012 trial. However, a decrease in microbial activity was observed during the Summer 2012 trial. Soil pH and soil moisture underwent similar fluctuations in control samples and experimental samples pointing to environmental conditions having a strong influence on both these soil parameters.
Comstock, JL, LeBlanc, HN & Forbes, SL 2016, 'Analysis of Decomposition Fluid Collected from Carcasses Decomposing in the Presence and Absence of Insects' in Kars, H & Eijkel, LVD (eds), Soil in Criminal and Environmental Forensics. Soil Forensics, Springer, Germany, pp. 275-296.View/Download from: Publisher's site
Most decomposition studies investigate soft tissue degradation in the presence of insects, however several studies have shown that when insect activity is excluded from carcasses, the rate of decomposition slows down. The goal of this study was to explore the effect of insect activity on the chemical properties of decomposition fluid. Fluid was collected from pig (Sus scrofa) carcasses over the course of two summer trials (2011 and 2012) conducted in southern Ontario, Canada. The pH and conductivity were measured and fatty acids were analysed using Attenuated Total Reflectance- Infrared (ATR-IR) spectroscopy. Results were compared between insect inclusion, partial exclusion, and complete exclusion carcass groups. The results indicate that the presence of insects increases the pH and decreases the conductivity of decomposition fluid. Spectral fatty acid results did not appear to vary greatly between experimental groups. The overall levels were not sufficiently different between carcass groups to conclude that the presence of insects played an important role in the fatty acid degradation process.
Forbes, SL & Carter, DO 2016, 'Processes and Mechanisms of Death and Decomposition of Vertebrate Carrion' in Benbow, ME, Tomberlin, JK & Taron, A (eds), Carrion Ecology, Evolution, and Their Applications, Taylor and Francis, Surrey, UK, pp. 13-30.View/Download from: Publisher's site
Stadler, S, Focant, JF & Forbes, SL 2016, 'Forensic Analysis of Volatile Organic Compounds from Decomposed Remains in a Soil Environment' in Kars, H & Eijkel, LVD (eds), Soil in Criminal and Environmental Forensics. Soil Forensics, Springer, Germany, pp. 297-316.View/Download from: Publisher's site
The detection of clandestine graves or concealed remains can pose a challenge to investigators. Research into the chemical signatures of decomposition, including volatile organic compounds (VOCs), can aid in the development of improved methods for the detection of remains and can further the understanding of decomposition processes. Over the last decade a number of studies have investigated decomposition VOCs from a variety of soil environments. However due to the variety of environments and methods used during these investigations a consistent odour signature remains elusive. This paper will discuss the complexity of decomposition odour and the current knowledge base of decomposition VOCs within soil environments including the impact of the entire death assemblage on the production of VOCs. The use of advanced instrumentation such as comprehensive two dimensional gas chromatography – time-of-flight mass spectrometry for the characterisation of decomposition odour is proposed. Incorporating advanced instrumentation and data handling tools into the analysis of decomposition odour will facilitate the comparison of odour profiles and generation of a consistent decomposition odour signature.
© 2016 Elsevier Ltd. All rights reserved. This chapter defines the term 'taphonomy' and summarizes the history of the study as pursued in various disciplines. Intrinsic and extrinsic variables that affect preservation of human remains are summarized. This is followed by an examination of the questions that forensic taphonomy can potentially address, including: what is the estimated time since death/postmortem interval or time since deposition/post-burial interval?; how did the remains come to be where they were located or discovered?; what actions may have taken place to conceal the victimas identity or the crime?; and which factors effect injury interpretation, specifically, differentiating perimortem trauma from postmortem changes?
Forbes, SL & Carter, DO 2015, 'Processes and mechanisms of death and decomposition of vertebrate carrion' in Carrion Ecology, Evolution, and Their Applications, pp. 13-30.View/Download from: Publisher's site
© 2016 by Taylor & Francis Group, LLC. The majority of the published literature referring to carrion ecology focusses on vertebrate decomposition as it is these larger organism's carcasses that typically survive long enough for the processes and mechanisms to be studied. Vertebrate bodies comprise various soft and hard tissues. The soft tissues consist of organs, muscles, ligaments, tendons, and hide, whereas the hard tissues make up the skeleton and include bone, teeth, cartilage, horn, and antler (Lyman 1994). Soft tissues will typically decay faster than hard tissues, and it is the dead and decaying tissues of the animal that are referred to as carrion. The hard tissues, especially bone, can be preserved for extended periods of time. Cartilage is harder than most soft tissues, but softer than bone, and occupies internal areas of the body that are not close to the skin surface. Horn is primarily keratin, the same protein which makes up hair, hoof sheaths, and feathers while antler resembles bone (Lyman 1994). Teeth are a different material and are largely composed of enamel and dentine, two of the hardest skeletal tissues in the body. The chemical and macrostructural properties of hard tissues make them resilient against the normal decomposition processes that impact soft tissues (Chapter 23). For this reason, they are often the only materials that survive in the natural environment.
Forbes, SL 2014, 'Taphonomy in Bioarchaeology and Human Osteology' in Smith, C (ed), Encyclopedia of Global Archaeology, Springer, New York, pp. 7219-7225.
Traditionally, taphonomy was studied by paleontologists to interpret the processes that operate on organic remains that comprise a part of the fossil record. A major focus of taphonomy was to understand the effects of those processes in order to reconstruct the past as it pertains to a particular fossil assemblage (Shipman 1981). Years later, archaeologists began to study taphonomy in order to determine how and why floral and faunal remains accumulated and differentially preserved within the archaeological record. Interpretation of the postmortem, pre-, and post-burial histories of faunal assemblages is critical in determining their association with hominid activity and behavior. Archaeologists typically separate natural from cultural processes when identifying evidence of human interaction with faunal remains (Lyman 1994).
Forbes, SL 2014, 'Time Since Death in Bioarchaeology and Human Osteology' in Smith, C & Smith, J (eds), Encyclopedia of Global Archaeology, Springer, New York, pp. 7308-7312.
Time since death (TSD) is defined as the time frame between death and discovery of an organism. When estimated in an archaeological context, this time frame may be referred to as time since deposition and in a forensic context can be termed postmortem interval. Time since death cannot be established with certainty and for this reason is provided as an estimate of the range of time encompassing the period when death occurred. A shorter postmortem interval is typically associated with a narrower time range, while a longer postmortem interval has a broader time range and includes a wider margin of error. Presently, there is no single indicator which provides a reliable or accurate measure of the time since death of an organism.
Forbes, SL & Dadour, IR 2009, 'The soil environment and forensic entomology' in Byrd, JH & Castner, JL (eds), Forensic Entomology: The Utility of Arthropods in Legal Investigations, CRC Press, United States, pp. 407-426.
Cadaver decomposition involves complex chemical processes that are readily influenced by surrounding conditions. A body decomposing in an outdoor environment will be affected by ecological conditions such as climate, vegetation, and the soil environment. The soil environment is particularly important, as the process of decomposition can be altered considerably by soil type, pH, moisture, and oxygen content. The type of soil environment will also affect the invertebrate fauna associated with decomposition. As a result, the rate of decomposition will vary for a body decomposing on the soil surface compared to a body decomposing in a burial environment. It is therefore important to consider the effect of the soil environment on entomological evidence collected as part of a forensic investigation. This review will discuss the chemical processes of decomposition and preservation, as well as the effect of the soil environment, and subsequently the insect fauna, on these processes. A better understanding of these processes is imperative in the application of forensic entomology.
Forbes, SL & Nugent, K 2009, 'Dating of anthropological skeletal remains of forensic interest' in Blau, S & Ubelaker, DH (eds), Handbook of Forensic Anthropology and Archaeology: World Archaeological Congress Research Handbooks, Left Coast Press, United States, pp. 164-173.
Stokes, KL, Forbes, SL, Benninger, LA, Carter, DO & Tibbett, M 2009, 'Decomposition studies using animal models in contrasting environments: evidence from temporal changes in soil chemistry and microbial activity' in Ritz, K, Dawson, L & Miller, D (eds), Criminal and Environmental Soil Forensics, Springer, Netherlands, pp. 357-377.View/Download from: Publisher's site
Traditionally, soil evidence in forensic science has focused predominantly on the transference of soil particles from a victim or suspect and a crime scene. However, a recent increase in forensic taphonomy research has highlighted the potential of soil to provide key information to an investigation involving decomposed remains. A decomposing carcass can release a significant pulse of nutrients into the surrounding soil (gravesoil) resulting in the retention of decomposition products in the soil for a considerable period of time. In order to understand the complex associations between a decomposing carcass and the soil system, research must be conducted in both controlled laboratory environments and outdoor field environments. This chapter discusses two contrasting decomposition studies which aimed to investigate the cadaver/soil interaction. The first study investigated the decomposition of small mouse carcasses buried in soil and was conducted within a controlled laboratory environment in Western Australia. The second study investigated the decomposition of large pig carcasses placed on the soil surface and was conducted in an outdoor field environment in southern Ontario. Both studies investigated a range of decomposition products particularly focusing on carbon-based, nitrogen-based and phosphorus-based compounds as these were considered to offer the most valuable information to address the research questions. The results of both studies provide the opportunity to comment on the effect of carcass size, soil type and decomposition environment on the influx of decomposition products into the soil.
Forbes, SL 2008, 'Decomposition chemistry in a burial environment' in Tibbett, M & Carter, DO (eds), Soil Analysis in Forensic Taphonomy: Chemical and Biological Effects of Buried Human Remains,, CRC Press, United States, pp. 203-223.
Forbes, SL 2008, 'Forensic chemistry: Applications to decomposition and preservation' in Marc Oxenham (ed), Forensic Approaches to Death, Disaster and Abuse, Australian Academic Press, Australia, pp. 233-242.
Forbes, SL 2008, 'Potential determinants of postmortem and postburial interval of buried remains' in Tibbett, M & Carter, DO (eds), Soil Analysis in Forensic Taphonomy: Chemical and Biological Effects of Buried Human Remains,, CRC Press, United States, pp. 225-246.
Zhang, W, Liu, T, Zhang, M, Zhang, Y, Li, H, Ueland, M, Forbes, SL, Rosalind Wang, X & Su, SW 2018, 'NOS.E: A New Fast Response Electronic Nose Health Monitoring System.', 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), International Conference of the IEEE Engineering in Medicine and Biology Society, IEEE, USA, pp. 4977-4980.View/Download from: Publisher's site
We present a practical electronic nose (e-nose) sys-tem, NOS.E, for the rapid detection and identification of human health conditions. By detecting the changes in the composition of an individual's respiratory gases, which have been shown to be linked to changes in metabolism, e-nose systems can be used to characterize the physical health condition. We demonstrated our system's viability with a simple data set consists of breath collected under three different scenarios from one volunteer. Our preliminary results show the popular classifier SVM can discriminate NOS.E's responses under the three scenarios with high performance. In future work, we will aim to gather a more varied data set to test NOS.E's abilities.
Buis, R, Rust, L, Nizio, K, Perrault, K, Rai, T, Stuart, B & Forbes, S 2017, 'IS HUMAN DECOMPOSITION FLUID A VALID TRAINING AID FOR CADAVER-DETECTION DOGS?', FORENSIC SCIENCE INTERNATIONAL, 21st Triennial Meeting of the International-Association-of-Forensic-Sciences (IAFS), ELSEVIER IRELAND LTD, Toronto, CANADA, pp. 252-252.
Forbes, SL, Wilson, M & Stuart, BH 2010, 'Examination of adipocere formation in Lake Ontario, Canada', 20th International Symposium on the Forensic Sciences Abstract Book, 20th International Symposium on the Forensic Sciences, Sydney.
Notter, SJ, Stuart, BH, Dent, BB & Forbes, SL 2009, 'The effect of water environment on adipocere formation', UTS Faculty of Science Research Day Book of Abstracts, UTS Faculty of Science Research Day.
Notter, SJ, Stuart, BH, Dent, BB & Forbes, SL 2009, 'The effect of water environment on adipocere formation', 4th Mediterranean Academy of Forensic Sciences Meeting Abstracts, 4th Mediterranean Academy of Forensic Sciences Meeting, Antalya, pp. 1-1.
Onishi, A, Thomas, P, Stuart, BH, Guerbois, JL & Forbes, SL 2007, 'TGMS analysis of the thermal decomposition of pig bone for forensic applications', Medicta 2007: The 8th Mediterranean Conference on Calorimetry and Thermal Analysis, 8th Mediterranean Conference on Calorimetry and Thermal Analysis, Palermo.
Onishi, A, Thomas, P, Stuart, BH, Guerbois, JL & Forbes, SL 2006, 'TGMS analysis of the thermal decomposition of compact pig bone', 9th European Symposium on Thermal Analysis and Calorimetry, Wydawnictwo Naukowe, Krakow.
Forbes, SL, Stuart, BH & Dent, BB 2005, 'Chemical characterisation of decomposition products in grave soils', 17th Meeting of the International Association of Forensic Sciences Abstracts, 17th Meeting of the International Association of Forensic Sciences, Hong Kong, pp. 1-1.
Forbes, SL, Stuart, BH, Dent, BB & Dadour, IR 2005, 'Factors affecting the formation of adipocere in soils', Proceedings of the American Academy of Forensic Science 57th Annual Meeting, AAFS, New Orleans, pp. 1-399.
Notter, SJ, Stuart, BH, Dent, BB & Forbes, SL 2005, 'The effect of acid-base chemistry on the formation of adipocere in grave soils', 17th Meeting of the International Association of Forensic Sciences Abstracts, 17th Meeting of the International Association of Forensic Sciences, Hong Kong.
Stuart, BH, Craft, L, Forbes, SL, Dent, BB & Dadour, IR 2005, 'Adipocere formation studied using FTIR-ATR spectroscopy', 17th Meeting of the International Association of Forensic Sciences, 17th Meeting of the International Association of Forensic Sciences, Hong Kong, pp. 1-1.
Australian Federal Police
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Fire and Rescue NSW
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Victorian Institute of Forensic Medicine
Ontario Provincial Police (Canada)