He’s been called the “go-to guy” for historical DNA casework in New South Wales, but David Bruce’s move to Western marks a turning point in his remarkable career. As well as using his 20 years of experience as a forensic DNA specialist in crime scene analysis, he’s now sharing his technical and industry knowledge with a new generation of scientists as he embarks on a new role as an Industry Associate Professor at Western.
David’s analysis of evidence in both cold and active cases has contributed to a swathe of convictions in NSW. In fact, so far in his twenty-year career at the NSW Forensic and Analytical Science Service (FASS) he has been able to find DNA links between many cases that police had previously thought were unconnected – shedding new light on the investigations that gave investigators new lines of inquiry, leading to convictions.
One of the most rewarding projects David has been involved in was a police initiative launched in 2008 to examine thousands of pieces of evidence from cold cases. “From about 1985, the forensic laboratory had a policy that if they detected biological material on crime scene exhibits, they would store that sample in a freezer,” said David. Even though the technology to use DNA to identify individuals did not exist until several years later, that foresight enabled David to recover DNA profiles in many cold cases. “The project was looking at cold cases, and applying new technology to them to give investigative leads. It was a four-year project, and it became my niche area. I was very passionate about that project.”
The project was remarkably successful. David and his colleagues looked at over 2,000 sexual assault cases and over 80 unsolved homicides. “We found several serial offenders,” David said. “It was incredibly useful to the police because they suddenly had leads. In one case there were five different cases of assaults on children, and our DNA testing linked the five incidents. The DNA profile still didn’t link to a suspect, but when the police looked at the cases as a whole they were able to find a person of interest that led to an arrest. There’s no statute of limitations on serious crime, and these cases are never forgotten and never closed.”
David refers to forensic DNA testing as “the gift that keeps on giving,” because the DNA analysis from cold cases is still leading to convictions as more reference DNA profiles from individuals are uploaded on to police databases. As DNA technology expands, David says more cold cases will be solved. “The police have unidentified remains where we have DNA information, but no way of identifying who that person is,” he explained. “Now we have the option of looking just at the Y chromosome, which becomes a method of familial linking. Mitochondrial DNA is also useful in degraded DNA, which is passed down through the maternal line.” These technologies may help investigators identify family members of unidentified remains, enabling investigators to identify people based on the DNA of more distant family members.
As well as extensive lab work, David has been called as an expert witness in numerous criminal cases, a skill he has developed and is keen to pass on to his forensics students. “I’m interested in what courts ask of expert witnesses,” David explained. “What’s becoming a big issue in criminal casework is the fact that DNA can be transferred and persist on an item for a long period of time. It’s important to get answers on the propensity for DNA to be transferred – whether it’s been deposited by direct or indirect transfer.”
While teaching at Western, David will be continuing his work as a forensic biologist at FASS, giving him a foot in both camps. “This will allow me to keep my students up to date with all the latest advancements in DNA technology,” he said.
David will be teaching second- and third-year Forensic Biology and supervising post graduate research projects at the Hawkesbury campus from 2022.
