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
Volatile Organic Compounds
Two-Dimensional Gas Chromatography
Investigation of Human Remains
Introduction to Forensic Taphonomy
© 2017 The Chartered Society of Forensic Sciences. 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 (GCGC-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-GCGC-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.
Di Maggio, R.M., Donnelly, L.J., Al Naimi, K.S., Barone, P.M., Da Silva Salvador, F.A., Dawson, L., Dixon, R., Fitzpatrick, R., Gradusova, O., Nesterina, E., Peleneva, M., Ushacova, O., Gallego, C.M.M., 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, R.C., Appleton, A.J. & Forbes, S.L. 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: UTS OPUS or 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, K.A., Megido, R.C., Dubois, L.M., Francis, F., Haubruge, E., Forbes, S.L., Focant, J.F. & Stefanuto, P.H. 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, M.A., Nizio, K.D., Ueland, M. & Forbes, S.L. 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: UTS OPUS or 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, K.D., Ueland, M., Stuart, B.H. & Forbes, S.L. 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 (GCGC-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, J.M., Forbes, S.L. & Stuart, B.H. 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, K.D., Perrault, K.A. & Forbes, S.L. 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: UTS OPUS or Publisher's site
Breton, H., Kirkwood, A.E., Carter, D.O. & Forbes, S.L. 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, S.J., Fahey, P., Forbes, S.L. & 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
© 2015 Australian Academy of Forensic Sciences. The development of new and more accurate methods for estimating post-mortem interval (PMI), which can be applied universally, are gaining in popularity. However, given the geographically specific nature of soft tissue decomposition, these methods need to be tested for their accuracy and applicability in a variety of regions before being applied to police and forensic investigations. This study tested two methods for PMI estimations to validate their applicability when used in the Hawkesbury region of New South Wales, Australia. The first method, referred to as the 'Accumulated degree day' (ADD) method, was proposed by Megyesi et al. 1 in 2005 and the second method, referred to as the 'Degree of decomposition index (DDI)' method, was proposed by Fitzgerald and Oxenham 2 in 2009. Four adult pig carcasses were placed on a soil surface and left to decompose undisturbed from July-September, 2013. The ADD and DDI methods were applied to the remains during this post-mortem interval. Results show that both methods under-estimated the time since death of the remains; however, the ADD method did have the potential to be effective when remains were in the advanced decomposition stages. Failure to validate these methods likely occurred because they could not account for the underlying factors affecting decomposition in this specific environment. An alternative equation was created for these methods, using data collected from the decomposition site in the Hawkesbury region and further validation is being carried out to account for inter- and intra-year variation.
Nizio, K.D., Cochran, J.W. & Forbes, S.L. 2016, 'Achieving a Near-Theoretical Maximum in Peak Capacity Gain for the Forensic Analysis of Ignitable Liquids Using GCGC-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 (GCGC) 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, K.A. & Forbes, S.L. 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, K.D. & Forbes, S.L. 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 (GCGC-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.
Wenholz, D.S., Luong, S., Philp, M., Forbes, S.L., Stuart, B.H., Drummer, O.H. & 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
Forbes, S.L., Troobnikoff, A.N., Ueland, M., Nizio, K.D. & Perrault, K.A. 2016, 'Profiling the decomposition odour at the grave surface before and after probing', Forensic Science International, vol. 259, pp. 193-199.View/Download from: UTS OPUS or 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 (GCGC–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, K.D., Perrault, K.A., Troobnikoff, A.N., Ueland, M., Shoma, S., Iredell, J.R., Middleton, P.G. & Forbes, S.L. 2016, 'In vitro volatile organic compound profiling using GCGC-TOFMS to differentiate bacteria associated with lung infections: a proof-of-concept study', Journal of Breath Research, vol. 10.View/Download from: UTS OPUS or 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 (GCGC-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, A.N., Frankham, G., Johnson, R.N. & Forbes, S.L. 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 (GCGC-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-GCGC-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.
Chun, L.P., Miguel, M.J., Junkins, E.N., Forbes, S.L. & Carter, D.O. 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.L., Desaulniers, J.P., LeBlanc, H.N. & Forbes, S.L. 2015, 'New decomposition stages to describe scenarios involving the partial and complete exclusion of insects', Journal of the Canadian Society of Forensic Science, vol. 48, no. 1, pp. 1-19.View/Download from: Publisher's site
© 2014 Canadian Society of Forensic Science. Few studies have intentionally examined the decomposition process when insects are excluded and only one known study has been published that has characterized decomposition occurring under this condition. This study proposes new stages of decomposition to describe scenarios involving the partial and complete exclusion of insects. Pig (Sus scrofa domesticus) carcasses were used to model the human decomposition process during the summer months of three consecutive years in Southern Ontario, Canada. The carcasses that were colonized by insects passed through the stages initially proposed by Payne (1965). Carcasses excluded from insects differed from these stages and warranted new stages to describe the processes. Partially excluded carcasses were characterized by: fresh, bloat, localized tissue removal, dry decomposition, and desiccation stages. The completely excluded carcasses were characterized by: fresh, bloat, deflation, and dry decomposition stages. Additional studies should be conducted in different environments to compare these observational stages.
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 (GCGC–TOFMS) is rapidly becoming more prevalent. The objective of this study was to compare GC–qMS and GCGC–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 GCGC–TOFMS allowed peak co-elutions, chromatographic artefacts, and dynamic range to be more easily addressed and managed. Furthermore, the software associated with GCGC–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 GCGC–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 GCGC–TOFMS in decomposition odour profiling is undoubtedly an asset in this field of research.
Stadler, S., Desaulniers, J.-.P. & Forbes, S.L. 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
Stefanuto, P.-.H., Perrault, K., Focant, J.-.F. & Forbes, S. 2015, 'Fast Chromatographic Method for Explosive Profiling', Chromatography, vol. 2, no. 2, pp. 213-224.View/Download from: UTS OPUS or 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 (GCGC) 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 GCGC, 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, K.A., Stadler, S., Pesesse, R., LeBlanc, H.N., Forbes, S.L. & Focant, J.-.F. 2015, 'GCGC-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
In forensic thanato-chemistry, the understanding of the process of soft tissue decomposition is still limited. A better understanding of the decomposition process and the characterization of the associated volatile organic compounds (VOC) can help to improve the training of victim recovery (VR) canines, which are used to search for trapped victims in natural disasters or to locate corpses during criminal investigations. The complexity of matrices and the dynamic nature of this process require the use of comprehensive analytical methods for investigation. Moreover, the variability of the environment and between individuals creates additional difficulties in terms of normalization. The resolution of the complex mixture of VOCs emitted by a decaying corpse can be improved using comprehensive two-dimensional gas chromatography (GCGC), compared to classical single-dimensional gas chromatography (1DGC). This study combines the analytical advantages of GCGC coupled to time-of-flight mass spectrometry (TOFMS) with the data handling robustness of supervised multivariate statistics to investigate the VOC profile of human remains during early stages of decomposition. Various supervised multivariate approaches are compared to interpret the large data set. Moreover, early decomposition stages of pig carcasses (typically used as human surrogates in field studies) are also monitored to obtain a direct comparison of the two VOC profiles and estimate the robustness of this human decomposition analog model. In this research, we demonstrate that pig and human decomposition processes can be described by the same trends for the major compounds produced during the early stages of soft tissue decomposition.
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.View/Download from: UTS OPUS
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, K.A., Rai, T., Stuart, B.H. & Forbes, S.L. 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: UTS OPUS or Publisher's site
© The Royal Society of Chemistry. Increased characterisation of decomposition odour has improved existing knowledge regarding the decomposition volatile organic compound (VOC) profile of carrion. Validation of this dynamic decomposition VOC profile is required in order to characterise the variables that affect their production. This study was performed to determine whether the decomposition VOC profile produced under field conditions differed between summer and winter in an Australian environment. Outdoor studies were conducted using pig carcasses as human analogues in order to assess seasonal variation in the decomposition process. Common decomposition VOCs were identified using comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (GCGC-TOFMS). Fewer compounds and reduced abundance of VOCs was observed during winter. Relationships between the levels of detected decomposition VOCs and weather variables were established to be stronger in winter. Weak relationships during summer suggested the potential that an underlying variable (e.g. microbial activity, insect activity) had a stronger relationship to the abundance of decomposition VOCs. The seasonal robustness of the decomposition VOC profile is important to fields relying on the presence of a decomposition odour, i.e. search and recovery of victims in mass disasters, homicides, and missing persons cases. This journal is
Perrault, K.A., Stefanuto, P.-.H., Stuart, B.H., Rai, T., Focant, J.-.F. & Forbes, S.L. 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: UTS OPUS or Publisher's site
Cadaver-detection dogs use volatile organic compounds (VOCs) to search for human remains including those deposited on or beneath soil. Soil can act as a sink for VOCs, causing loading of decomposition VOCs in the soil following soft tissue decomposition. The objective of this study was to chemically profile decomposition VOCs from surface decomposition sites after remains were removed from their primary location.Pig carcasses were used as human analogues and were deposited on a soil surface to decompose for 3 months. The remains were then removed from each site and VOCs were collected from the soil for 7 months thereafter and analyzed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GCGC-TOFMS).Decomposition VOCs diminished within 6 weeks and hydrocarbons were the most persistent compound class. Decomposition VOCs could still be detected in the soil after 7 months using Principal Component Analysis.This study demonstrated that the decomposition VOC profile, while detectable by GCGC-TOFMS in the soil, was considerably reduced and altered in composition upon removal of remains. Chemical reference data is provided by this study for future investigations of canine alert behavior in scenarios involving scattered or scavenged remains.
Perrault, K.A., Stefanuto, P.-.H., Stuart, B.H., Rai, T., Focant, J.-.F. & Forbes, S.L. 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: UTS OPUS or 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, K.A., Lloyd, R.M., Stuart, B., Rai, T., Forbes, S.L. & Focant, J.-.F. 2015, 'Exploring new dimensions in cadaveric decomposition odour analysis', Anal. Methods.View/Download from: UTS OPUS or Publisher's site
Ueland, M., Nizio, K.D., Forbes, S.L. & Stuart, B.H. 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: UTS OPUS or 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.
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, S.L., Perrault, K.A., Stefanuto, P.-.H., Nizio, K.D. & 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: UTS OPUS or 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 (GCGC-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 GCGC-TOFMS were demonstrated for d...
Ruffell, A., Pringle, J.K. & Forbes, S.L. 2014, 'Search protocols for hidden forensic objects beneath floors and within walls', Forensic Science International, vol. 237, pp. 137-145.View/Download from: UTS OPUS or 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.
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, S.L. 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: UTS OPUS or 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, S.L. 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: UTS OPUS or Publisher's site
Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCGC-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), GCGC-TOFMS is the tool of choice for cadaveric VOC profiling.
Forbes, S.L., 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: UTS OPUS or 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, S.L. 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: UTS OPUS or 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, D.O., Gaspari, F., O'Brien, R.C. & Forbes, S.L. 2013, 'Ground penetrating radar use in three contrasting soil textures in southern Ontario', Geological Society, London, vol. 384, pp. 221-228.View/Download from: UTS OPUS or 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, S.L. 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: UTS OPUS or 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, S.L. & 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: UTS OPUS or 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, K.L., Forbes, S.L. & 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: UTS OPUS or 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, S.L., Mayes, R. & Forbes, S.L. 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: UTS OPUS or 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, D.O., Gaspari, F., O'Brien, R.C., Stuart, B.H. & Forbes, S.L. 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: UTS OPUS or 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, J.D., Brokl, M., Forbes, S.L. & 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: UTS OPUS or 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, B.H., Dent, B.B., Notter, S.J., Forbes, S.L., O'Brien, C. & Dadour, I.R. 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: UTS OPUS or 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, S.L., Wilson, M.A. & Stuart, B.H. 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: UTS OPUS or 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, S.L. 2010, 'Steam development of latent fingerprints on thermal paper', Journal of Forensic Identification, vol. 60, no. 6, pp. 619-638.View/Download from: UTS OPUS
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, S.L. 2010, 'An investigation of barefoot morphology, friction ridges and their significance in forensic identification', Identification Canada, vol. 33, pp. 4-19.View/Download from: UTS OPUS
O'Brien, R.C., Forbes, S.L., 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: UTS OPUS or 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, R.C., Larcombe, A., Meyer, J., Forbes, S.L. & Dadour, I. 2010, 'The scavenging behaviour of the Australian Raven (Corvus coronoides): patterns and influencing factors', Sylvia, vol. 46, pp. 133-148.View/Download from: UTS OPUS
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, G.E., Forbes, S.L. & Lewis, S.W. 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: UTS OPUS or 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, S.L. & Lewis, S.W. 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: UTS OPUS or 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, L.M., Forbes, S.L. & Lewis, S.W. 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: UTS OPUS or 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, L.M., Forbes, S.L. & Lewis, S.W. 2010, 'Analytical separations of mammalian decomposition products for forensic science: A review', Analytica Chimica Acta, vol. 682, pp. 9-22.View/Download from: UTS OPUS or 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, K.L., Forbes, S.L. & 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: UTS OPUS or 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, L.E., Carter, D.O. & Forbes, S.L. 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: UTS OPUS or 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, L.A., Carter, D.O. & Forbes, S.L. 2008, 'The biochemical alteration of soil beneath a decomposing carcass', Forensic Science International, vol. 180, no. 2-3, pp. 70-75.View/Download from: UTS OPUS or 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, S.C., Forbes, S.L. & Dadour, I.R. 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: UTS OPUS or 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, C.J. & Forbes, S.L. 2008, 'An investigation of the vegetation associated with grave sites in southern Ontario', Canadian Society of Forensic Science Journal, vol. 41, pp. 199-207.View/Download from: UTS OPUS
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, B.H., Guerbois, J.L. & Forbes, S.L. 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: UTS OPUS or 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, R.C., Forbes, S.L., Meyer, J. & Dadour, I.R. 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, B.H., Guerbois, J.L. & Forbes, S.L. 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: UTS OPUS or 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.
Forbes, S.L., Dent, B.B. & Stuart, B.H. 2005, 'The effect of soil type on adipocere formation', Forensic Science International, vol. 154, no. 1, pp. 35-43.View/Download from: UTS OPUS or Publisher's site
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
Forbes, S.L., Stuart, B.H. & Dent, B.B. 2005, 'The effect of the burial environment on adipocere formation', Forensic Science International, vol. 154, no. 1, pp. 24-34.View/Download from: UTS OPUS or Publisher's site
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
Forbes, S.L., Stuart, B.H. & Dent, B.B. 2005, 'The effect of the method of burial on adipocere formation', Forensic Science International, vol. 154, no. 1, pp. 44-52.View/Download from: UTS OPUS or Publisher's site
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
Forbes, S.L., Stuart, B.H., Dent, B.B. & Fenwick-Mulcahy, S. 2005, 'Characterization of adipocere formation in animal species', Journal Of Forensic Sciences, vol. 50, no. 3, pp. 633-640.View/Download from: UTS OPUS
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
Stuart, B.H., Forbes, S.L. & Dent, B.B. 2005, 'Studies of adipocere using attenuated total reflectance infrared spectroscopy', Forensic Science, Medicine and Pathology, vol. 1, no. 3, pp. 197-201.View/Download from: UTS OPUS
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.
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.
Forbes, S.L., Stuart, B.H., Dadour, I.R. & Dent, B.B. 2004, 'A preliminary investigation of the stages of adipocere formation', Journal Of Forensic Sciences, vol. 49, pp. 566-574.View/Download from: UTS OPUS
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, S.L., Keegan, J., Stuart, B.H. & Dent, B.B. 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: UTS OPUS or Publisher's site
Forbes, S.L., Stuart, B.H. & Dent, B.B. 2002, 'Identification of adipocere in grave soils', Forensic Science International, vol. 127, no. N/A, pp. 225-230.View/Download from: UTS OPUS or 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, B.H., Forbes, S., Dent, B.B. & 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
Breton, H.A., Kirkwood, A.E., Carter, D.O. & Forbes, S.L. 2016, 'Changes in Soil Microbial Activity Following Cadaver Decomposition During Spring and Summer Months in Southern Ontario' in Soil in Criminal and Environmental Forensics. Soil Forensics, Springer, Germany, pp. 243-262.View/Download from: UTS OPUS or 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, J.L., LeBlanc, H.N. & Forbes, S.L. 2016, 'Analysis of Decomposition Fluid Collected from Carcasses Decomposing in the Presence and Absence of Insects' in Soil in Criminal and Environmental Forensics. Soil Forensics, Springer, Germany, pp. 275-296.View/Download from: UTS OPUS or 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, S.L. & Carter, D.O. 2016, 'Processes and Mechanisms of Death and Decomposition of Vertebrate Carrion' in Benbow, M.E., Tomberlin, J.K. & 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, J.F. & Forbes, S.L. 2016, 'Forensic Analysis of Volatile Organic Compounds from Decomposed Remains in a Soil Environment' in Soil in Criminal and Environmental Forensics. Soil Forensics, Springer, Germany, pp. 297-316.View/Download from: UTS OPUS or 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.
Forbes, S.L. 2014, 'Taphonomy in Bioarchaeology and Human Osteology' in 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, S.L. 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, S.L. & Dadour, I.R. 2009, 'The soil environment and forensic entomology' in Byrd, J.H. & Castner, J.L. (eds), Forensic Entomology: The Utility of Arthropods in Legal Investigations, CRC Press, United States, pp. 407-426.View/Download from: UTS OPUS
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, S.L. & Nugent, K. 2009, 'Dating of anthropological skeletal remains of forensic interest' in Blau, S. & Ubelaker, D.H. (eds), Handbook of Forensic Anthropology and Archaeology: World Archaeological Congress Research Handbooks, Left Coast Press, United States, pp. 164-173.
Stokes, K.L., Forbes, S.L., Benninger, L.A., Carter, D.O. & 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: UTS OPUS or 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, S.L. 2008, 'Decomposition chemistry in a burial environment' in Tibbett, M. & Carter, D.O. (eds), Soil Analysis in Forensic Taphonomy: Chemical and Biological Effects of Buried Human Remains,, CRC Press, United States, pp. 203-223.
Forbes, S.L. 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.View/Download from: UTS OPUS
Forbes, S.L. 2008, 'Potential determinants of postmortem and postburial interval of buried remains' in Tibbett, M. & Carter, D.O. (eds), Soil Analysis in Forensic Taphonomy: Chemical and Biological Effects of Buried Human Remains,, CRC Press, United States, pp. 225-246.
Forbes, S.L., Wilson, M. & Stuart, B.H. 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, S.J., Stuart, B.H., Dent, B.B. & Forbes, S.L. 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, S.J., Stuart, B.H., Dent, B.B. & Forbes, S.L. 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, B.H., Guerbois, J.L. & Forbes, S.L. 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, B.H., Guerbois, J.L. & Forbes, S.L. 2006, 'TGMS analysis of the thermal decomposition of compact pig bone', 9th European Symposium on Thermal Analysis and Calorimetry, Wydawnictwo Naukowe, Krakow.
Forbes, S.L., Stuart, B.H. & Dent, B.B. 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, S.L., Stuart, B.H., Dent, B.B. & Dadour, I.R. 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, S.J., Stuart, B.H., Dent, B.B. & Forbes, S.L. 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, B.H., Craft, L., Forbes, S.L., Dent, B.B. & Dadour, I.R. 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.
Stuart, B.H., Forbes, S.L., Craft, L. & Dent, B.B. 2005, 'Infrared spectroscopy of adipocere', Proceedings of the 6th Australian Conference on Vibrational Spectroscopy, ACOVS6 Organising Committee, Sydney.
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