Answering the questions that no one else can

Can bullets be identified after being in a decomposed body? 

It might not be a question that many of us ask, but after years working with firearms in the Australian Defence Force, NSW Police and Australian Federal Police (AFP), it’s safe to say that the questions Matthew asks may be very different to the general population.

And, he has a lot of them.

A career’s worth of questions

“The majority of the questions that I've had throughout my career have all come out of case work,” Matthew reflects.

“When I was at NSW Police I did more field-based work, so I attended crime scenes where people have been killed and the post-mortems that follow on from the scene. A lot of questions would be raised by the detectives or the pathologists, and some of which I didn't know the answer to, and couldn't find the answer anywhere.”

When UTS invited Matthew and his AFP colleagues for a tour of its unique body donation facility dedicated to the study of forensic taphonomy (the study of what happens to a human body after death), he decided to satisfy his curiosity.

“As we were wandering around, I was just thinking of a thousand ideas. So, I approached UTS to ask if I could undertake this project.”

Day-to-day Matthew works for a section of the AFP that helps the Australian Border Force to identify and classify firearms. His training for this role – which took over three years of study, written exams, practical assessments and a panel assessment – has deemed him to be a firearms expert by the National Institute of Forensic Science. 

He’s one of fewer than 30 experts in Australia who have the credibility to classify firearms and toolmarks – the unique marks left on bullets when they’re shot from a gun.

“As the bullet travels down the barrel of the firearm, scratch marks, called striae, are made on the bullet. Each barrel leaves its own individual marks that we can identify,” Matthew explains.

With this knowledge, Matthew can identify which gun fired the bullet, which can significantly aid an investigation. 

“I match the gun to the bullet. Then it’s up to the detectives to put that gun in someone’s hands.”

Answerless questions are answered

While at UTS’s facility Matthew started to wonder what would happen to the bullet, and its identifiable marks, once a body had decomposed.

“I was interested in seeing if a bullet is subjected to decomposition. Does it corrode the bullet? At what point can you no longer identify the bullet?”

Leveraging his network of firearm expert colleagues around Australia in a blind test, they were consistently able to microscopically identify the bullet with the firearm for up to three weeks after it was inserted in winter, and only three days in summer. 

These results can help to provide detectives with the potential time the person may have died.