How police around Australia are cracking cold cases using investigative genetic genealogy
Kerryn Tate was murdered in 1979, and advancements in DNA technology have identified a suspect in the case. (Supplied: WA Police)
Described as WA's biggest cold case breakthrough since the introduction of new DNA technology, the naming of Terence John Fisher as a suspect in the 1979 murder of Perth woman Kerryn Tate created headlines around the country.
But for those who specialise in genetics and forensic work it came as no surprise, and they believe it could be part of the new normal when it comes to solving old crimes.
"I'd be expecting this to happen in quite a lot of cold cases now," said Dr Jemma Berry, who has a PhD in genetics, and lectures in genetics and forensic science at Edith Cowan University.
Police say those who had believed they had gotten away with major violent crimes can no longer rest easy.
Senior Constable Lisa Rosenberg issued a warning to criminals that advancements in DNA technology would mean more cold cases are solved. (ABC News )
"Finally they're looking over their shoulder, instead of the victims and their families," said Senior Constable Lisa Rosenberg, who specialises in Investigative Genetic Genealogy (IGG) with WA Police.
She played a major role in the breakthrough case of Ms Tate.
"If someone knocks on the door or they're getting pulled over, we'll be coming for you," Senior Constable Rosenberg said.
Terence John Fisher died in 2000, but he has now been named as a suspect in the 1979 murder of Kerryn Tate. (Supplied: WA Police)
The breakthrough was possible due to new techniques in tracing DNA in investigations.
How exactly does it work?
Thanks to a spike in the popularity of ancestry websites as people look to learn more about their family history, police have access to more DNA data, which they can use to identify familial matches.
"This is not necessarily a development in DNA technology, these ancestry websites and the DNA analysis has been around for a really long time, it's just a totally different way of looking at the DNA," Dr Berry said.
"What they're really looking for is familial relationships, links to other people in a suspect's family tree that they can then use to start their genetic search.
"And then finding those links to people in that family tree that could then potentially be a suspect for these cases."
But the method requires a remarkable amount of time and resources, which the Tate case illustrates.
It involved going through the profiles of more than 10,000 people, all the way back to the 1600s.
"Most of our matches were six to seven generations away from our person," Senior Constable Rosenberg said.
"We have four people in our team and we worked on this pretty much non-stop for 12 months until we identified that one person."
Can my family data be used?
Police have downplayed concerns people may have regarding law enforcement having access to their DNA profiles, emphasising the information from the websites is publicly accessible, and those who use the sites have the option as to whether they allow the data to be shared with police.
"I can't see the concerns and if people don't want to upload they don't have to, but if they've already got their DNA on these databases, millions of people worldwide are seeing that data, so I don't see why we can't," Ms Rosenberg said.
"That's all we see, just what they see.
Police currently only have access to two DNA databases. (ABC News)
"If you're allowing all of these millions of strangers around the world to look at your DNA data, it's not a big question for me to tick that box and allow law enforcement to solve serious crimes."
Dr Berry said she would also have no concerns sharing her data.
"I personally haven't done anything that the police need to worry about, but that doesn't say some third cousin twice removed in my family might not have," she said.
"But you know what, I'd rather they get caught and prosecuted for something like that than be left free in the community."
Do police have access to enough data?
For now, WA Police only have access to the databases of two genealogy websites.
It's prompted a public plea for people to upload their DNA and make it available to them, to help police solve violent crimes.
"We use GEDmatch and FamilyTreeDNA at the moment," Senior Constable Rosenberg said.
"There are other databases starting up but the numbers are just too small for us to use at the moment.
"Of those, probably only 10 per cent have opted in for law enforcement.
"We're just asking members of the public to upload to GEDmatch or FamilyTreeDNA."
Do police expect more breakthroughs?
Experts describe DNA technology as forever improving, and as it evolves, it's hoped more cold case crimes can be solved more easily.
"It's a great investigative tool, and it's only getting better with technology and the changes that we see coming, we're only getting better," Ms Rosenberg said.
Dr Berry agrees.
Dr Jemma Berry has a PhD in genetics, and expects further breakthroughs as the technology improves. (Supplied)
"DNA technology is rapidly evolving, there's new things coming out all of the time," she said.
"With all the new advancements in DNA technology there's always an application for those in the forensic sphere."
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