Sergeant Lesley Walker is a Scientific Officer based in Cairns. She is one of those forensic scientists you see on all the best TV crime shows and indeed, it was her fascination for watching those shows that helped shape her career in the Queensland Police Service (QPS).
But in fact, her initial career choice had nothing to do with policing. Her first passion was marine biology and after school, she completed a Bachelor of Science majoring in biochemistry and marine biology followed by a year of honours at James Cook University in Townsville.
By the time she’d finished all that study, she said she was itching to leave the books behind and start working.
“Having gone straight from school to four years of uni, I just wanted to get out there and start earning some money,” Sergeant Walker said.
“There weren’t a lot of jobs going for marine biologists, so policing was a fall back plan. It wasn’t that I’d come from a policing family or anything, but I was always interested in cop shows on TV, and the police service offered job security and plenty of opportunities for advancement.
“So I decided to join up in 1999, made it through the selection process and underwent my recruit training at the QPS Academy at Oxley, Brisbane.”
Sergeant Walker graduated from the academy and was appointed to a position in Cairns as a First Year Constable. It wasn’t until she was on the beat in Cairns that she began to think about combining her love of science with her policing career.
“We had a series of orientation sessions where officers from different sections throughout the Service came and talked to us about the options for specialising later on in our career,” Sergeant Walker said.
“Someone from the Scientific Section came and spoke and it was only then I realised I could pursue my passion for science and still be a police officer. I started looking into it.
“You had to serve in General Duties for three years first, but then, just as I came up to my three year mark, a position came up in Cairns. The field of forensic science wasn’t as big in the QPS as it is now, so I jumped at the chance and was lucky enough to be accepted,” she said.
Sergeant Walker joined the Scientific Section as a constable in 2003, and spent the next two years living in Brisbane undergoing training. This involved on the job training as well as a return to the books, completing a Masters Degree in Forensic Science at Griffith University part-time.
Currently, police qualifying as Scientific Officers are able to complete their on the job training in blocks rather than having to make a complete move to another city as Sergeant Walker did. Officers who already have a science degree are able to upgrade by completing a Graduate Certificate in Crime Scene Investigation.
Sergeant Walker explained that not all officers working in the field of forensic science had the higher qualification.
“In the QPS, there are different aspects to working in Forensic Services. You can either become a Scenes of Crime Officer (SOCO), or work in the Scientific Section. The SOCOs process what we call the volume crime such as break and enters and vehicle theft. They go out to crime scenes and take fingerprints and photographs and other forensic evidence. They don’t need to have science degrees,” Sergeant Walker said.
“The Scientific Officers on the other hand work on major crime such as rapes and murders. We have to have a science degree with a graduate diploma or similar in Forensic Science because we work extensively with chemicals to enhance biological evidence at crime scenes. We can be called on to give an expert opinion in a court of law or explain to a jury how a colour change has occurred in the presence of blood or seminal fluid.
“At a major crime scene, Scientific Officers and SOCOs both work together, but only we can give our opinion and expert evidence in court,” she said.
The other consequence of having higher qualifications is an accelerated progression through the ranks in the QPS. Sergeant Walker joined the Scientific Section as a constable, was promoted to senior constable after one year of extra study, and then promoted to the rank of sergeant after she had completed her Master in Forensic Science. While other police officers progressing to the rank of sergeant were completing assignments in the Management Development Program, she was completing a thesis comparing the qualities of Luminol and Blue Star, chemicals that react to otherwise invisible traces of blood and cause them to glow bright blue.
Sergeant Walker has worked on a number of high profile criminal cases, such as the deaths of eight children allegedly murdered by their mother in Cairns in 2014, as well as many cases that don’t make it into the media. She said one of the “curliest” cases she had worked on involved some pretty extreme measures.
“We had a case in 2011 where a husband reported his wife missing. His version of events surrounding her disappearance didn’t add up, so investigators looked deeper. They discovered he had purchased 60 litres of hydrochloric acid and had been seen later with a wheelie bin near the drain in front of his house,” Sergeant Walker said.
“So they called in Scientific. I jumped down the drain and spent a day going through all the rocks and debris and eventually found three sets of porcelain teeth, which we matched back to her through dental records.
“The woman weighed about 50kg when she disappeared, so we conducted an experiment using a 50kg pig cadaver to see if it would dissolve in 60 litres of hydrochloric acid. We often use pigs as analogs because they are as anatomically as close as we can get to humans, and in this case, we proved that yes, it was possible.
“This gave the investigators vital information to help them prosecute the case. And this is a good opportunity to make the point that forensics is not the be all and end all of solving crimes. You won’t ever solve a crime 100% using forensic science—rather you assist investigators by proving or disproving certain claims made by witnesses, victims or suspects. That’s what our job is about.”
Sergeant Walker said this case also gave people an idea of what kind of person would be able to do well as a Scientific Officer.
“It’s quite glamorised on TV, but the work is very meticulous and you have to be patient and have a real eye for detail. Jobs can be extremely time consuming—I spent five days examining the crime scene in the acid case.
“I think women are actually quite suited to this work, and there are now more women than there are men in many places. Up here in Cairns we have a male officer-in-charge, but all my other colleagues are women,” she said.
While crime shows are fascinating to TV viewers and can attract people such as Sergeant Walker to policing, the downside is that offenders are also becoming more forensically aware when they commit crimes.
“Criminals committing break and enters are certainly clever enough to wear gloves and this makes the job harder for police. However, many major crimes are either drug related or domestic violence related and more often than not, offenders will dig themselves into a hole by telling one lie and then another.
“But no matter what, we all leave traces of evidence, and we scientific officers do still have a few tricks up our sleeve to catch them out,” Sergeant Walker said.