For the first time, a Canadian police force has confirmed it's using the same genetic genealogy technique that finally caught the suspected Golden State Killer to solve a cold case of its own.

Vancouver police have hired U.S. firm Parabon NanoLabs to search all available genealogical records in hopes of finding any link to a suspected killer's DNA. The sample was collected in the West End apartment where Edgar Leonardo's body was found in 2003.

Parabon scours public genealogical sites such as GEDmatch and FamilyTreeDNA, which allow police to access their databanks. Most other well-known DNA testing companies don't co-operate with law enforcement without search warrants.

The goal is to either find a perfect match or identify relatives who might be able to lead detectives to the killer.

It's the same method that's led to dozens of recent arrests in cold cases south of the border, including the capture of the suspected Golden State Killer, who police say is responsible for a spree of break-ins, rapes and murders that terrorized multiple counties in California between 1974 and 1986.

Joseph James DeAngelo, 73, was arrested in April 2018 and charged with 13 murders. He's also suspected in at least 50 sexual assaults.

The Leonardo cold case

Vancouver homicide detective Sgt. Mike Heard recently spoke with CBC News outside the apartment building where 36-year-old Edgar "Iggy" Leonardo was found dead 16 years ago.

"I think about what the original investigator saw in 2003 and I look at the lay of the land and I wonder, you know, which way the suspect left," Heard said on the sidewalk, beside the older building in the densely populated downtown neighborhood.

The original investigator on the case retired several years ago, leaving Heard to pick up the killer's trail.

Sgt. Mike Heard stands in front of the apartment building in Vancouver's West End where 'Iggy' Leonardo was found dead 16 years ago. (Ben Nelms/CBC)

Police think Leonardo met someone in Vancouver's gay village late on the night of Aug. 23, 2003, and brought him home.

"And that's when he was murdered in here," said Heard, gesturing up at the seven-storey building. Police aren't releasing details about how Leonardo was killed or where exactly his body was found in his apartment.

Heard said police have good DNA evidence, but it doesn't match anything in the Canadian law enforcement databank, which only includes DNA records of convicted criminals.

But he's optimistic that with recent breakthroughs using genetic genealogy, they will soon find their suspect.

Solving some of the toughest cold cases

Police investigating the Golden State Killer case also had DNA evidence, but like the Vancouver detectives, couldn't find a direct match in law enforcement databanks.

In 2018, they tried a new technique. Rather than look for a 100 per cent match in criminal databanks, they searched beyond police records for any relatives, no matter how distant.

They started by comparing their samples with genetic records housed on GEDmatch, an open source ancestry site that co-operates with police and holds DNA profiles of about 1,000,000 people.

GEDmatch started in 2010 to help genealogists and amateurs dig deeper into their history and help connect adoptees with their biological relatives. When you upload your genetic profile to the site, you're asked to accept that it could be shared with law enforcement.

Using GEDmatch, police were able to identify more than a dozen people with genetic markers linking them to the suspected killer.

Authorities in California say Joseph James DeAngelo was identified using DNA evidence as the serial predator dubbed the Golden State Killer. (Fred Greaves/Reuters)

Genealogist Barbara Rae-Venter worked with investigators to build an elaborate family tree. Traditional police work helped fill in some of the missing branches.

After the search was narrowed down to two possible suspects, police tailed DeAngelo and obtained his DNA from a car door handle. It matched their crime scene sample, leading to DeAngelo's arrest at his home near Sacramento on April 24, 2018.

DeAngelo had worked as a police officer in northern California for six years starting in 1973. Investigators believe the knowledge he gained on the job helped him avoid arrest for so long.

Canadian couple killed in Washington state

Similar investigative techniques led to an arrest in a cold case involving a young Canadian couple who were killed in Washington state in 1987.

Tanya Van Cuylenborg, 18, and Jay Cook, 20, were on a quick road trip to Seattle but never made it back home to Victoria.

Van Cuylenborg's body was found in a ditch near Bellingham and Cook's remains were found about 100 kilometres away, near the Snoqualmie River in Snohomish County.

Tanya Van Cuylenborg and Jay Cook, both of Victoria, were killed during a trip to Seattle in November of 1987. (Van Cuylenborg and Cook families)

Tanya's brother, John Van Cuylenborg, knew for years that police had a sample of what they believed was the killer's DNA, but they couldn't find a match.

"That always ate away at me because it sure didn't feel right that somebody wouldn't be held accountable, that this wasn't going to be solved," he said in a recent interview with CBC at his home in Victoria.

John Van Cuylenborg says the technology that cracked his sister's cold case should be widely used in Canada to help families of victims find closure. (Chris Corday/CBC)

Tanya's best friend, May Robson, was devastated when she learned her friends had been killed.

"My world just shook. I mean we were young, we were starting out our lives, and to learn that there's evil in the world was shocking."

An arrest — 31 years later

Then, last year, 31 years after the killings, truck driver William Earl Talbott was tracked down and charged with two counts of murder.

Robson was elated. "I just could not believe it. And then the more I learned about the technology that was used, it was just, it was a miracle."

Police in Washington state say they used information from public genealogy websites to pinpoint William Earl Talbott as a suspect in the killings of Cook and Van Cuylenborg. They arrested him after collecting a DNA sample from a cup that fell from his vehicle and confirming it matched a sample from a crime scene. (Charles Biles/Associated Press)

In Talbott's case, that miracle was finding a relative with similar genetic markers, which eventually helped point investigators to Talbott as the prime suspect.

And as with the Golden State Killer case, Parabon NanoLabs did much of the work using GEDmatch.

Police say they confirmed Talbott, 55 at the time of his arrest, was their suspect by following him and eventually collecting a DNA sample from a coffee cup he had used.

DNA testing meets the traditional family tree

At the British Columbia Institute of Technology in Burnaby, Steen Hartsen demonstrated how DNA is collected from a discarded paper coffee cup pulled from the trash.

"I'm going to swab the outside of the cup, where his lips touched the cup," he said, rubbing a white swab over the rim and then depositing the tip into a vial for testing.

Hartsen, who teaches forensic science, says the new DNA testing is able to compare thousands of genetic markers, whereas older technology could only examine a handful.

"You're able to create these family trees where you might be able to associate people who only share a great-great-great-grandparent, whereas the older technology just wasn't able to do that."

Steen Hartsen, left, a forensic science instructor at the British Columbia Institute of Technology, says advances in DNA technology are helping investigators to find suspects they may never have tracked down otherwise. (Greg Rasmussen/CBC)

Combined with the growing popularity of DNA databanks, genetic genealogy provides a powerful tool to cross-reference police samples and make connections.

More than 26 million people have provided DNA samples to companies such as AncestryDNA and 23andMe. It could hit 100 million by 2021, according to the MIT Technology Review.

Although GEDmatch and some other DNA databanks openly co-operate with police, others do not.

The use of all of these databanks by police investigators has raised legal questions that the courts have yet to answer in Canada or the U.S.

Although there have been arrests and charges, judges, defence lawyers and prosecutors are arguing over the issues raised by this new technique. The first full-fledged trial will be Talbott's, which is set to begin in Washington next month.

Tricky legal issues ahead

Vancouver criminal defence lawyer Tony Paisana says it's only a matter of time until this type of evidence becomes the focus of a trial in a Canadian courtroom.

He thinks the key question will be: Whose rights have possibly been violated — the rights of the accused, or those of the relative whose DNA was used?

It's tricky, he says, because these broader searches of DNA databanks usually lead investigators to distant relatives of the person they are actually after.

"That creates the sort of interesting issue of whether or not the person on trial has a privacy interest in the DNA profile of someone else, be it a brother or sister or whoever it is that ends up having their sample given to the police."

To police, genetic genealogy is a potential windfall that could narrow the pool of suspects to a handful, at which point traditional investigative techniques can take over.

However, at the moment, the only legislation in Canada that deals with DNA evidence is the DNA Identification Act of 1998, which created a national databank and gave judges the power to order criminals to submit samples.

It doesn't address the issues raised with this new investigative technique.

Homicide investigator Sgt. Mike Heard says genetic genealogy is the breakthrough Canadian police have been waiting for. (Ben Nelms/CBC)

With a suspect finally in custody three decades after his sister's death, John Van Cuylenborg is calling for the federal government to clarify the rules for police.

"If it requires some legislative amendments or revisions, then so be it," he said. "I would be disappointed in Canadian society if we decided not to make use of this investigative tool."

Solving a cold case in Vancouver

Police are cautious because of the potential legal issues, and many police forces in this country were reluctant to comment when CBC approached them to discuss the topic.

After weeks of back and forth, Canada's national police force, the RCMP, told CBC News it is interested in this emerging investigative technique, but won't say if it's using it in any of its investigations.

A spokesperson wrote: "When it comes to public databases (i.e. ancestry.ca ), the RCMP is aware that some Canadian police agencies are currently exploring the use of genetic genealogy in criminal investigations. This includes the RCMP."

Back in Vancouver, Sgt. Mike Heard is convinced genetic genealogy will help solve the Leonardo cold case, as well as many other unsolved crimes across the country.

"I'm a firm believer," he said.

After all, it only takes one match with a distant relative.