Five questions about genetic genealogy and how police use it

A suspect image created by DNA profiling depicts what the suspect may have looked like at 25 years old, 45 years old and 65 years old. (Snohomish County Sheriff's Office)

VANCOUVER - Police in Washington state used a controversial new investigative technique they say helped them solve the murder of Victoria-area resident Tanya Van Cuylenborg, who was killed more than 30 years ago. Here are five questions about the genetic genealogy:

HOW WAS IT USED TO IDENTIFY A SUSPECT?

Detectives uploaded a DNA sample from the crime scene to an open-source genealogy database called GEDMatch. From there, they identified ancestors and relatives of their suspect. Genealogists then built a family tree, incorporating marriage records and other information, and worked their way backward to find a potential suspect. Police then collected a DNA sample from a cup the suspect had discarded.

HOW OFTEN HAS IT BEEN USED BY POLICE?

That's not known. The highest profile case was the arrest of Joseph DeAngelo, the so-called Golden State Killer who is accused of committing dozens of rapes and murders across California beginning 40 years ago. Last month, Washington state police announced the arrest of William Earl Talbott, who is accused of first-degree murder in the death of Van Cuylenborg. Her body was found in 1987. Neither of the charges have been proven in court. Parabon NanoLabs, which assisted in the Talbott case, says it has led police to three offenders in cold cases dating back 20 years.

IS THE PROCESS BEING USED IN CANADA?

Both genetic genealogist CeCe Moore and Parabon NanoLabs CEO Steven Armentrout declined to say whether they have helped Canadian law enforcement in cases using the same process as the Talbott case. The Canadian Association of Chiefs of Police says it is not aware of reverse genealogy being used in the Canadian context.

DO PRIVACY LAWS GOVERN THE USE OF GENEALOGY WEBSITES BY CANADIAN POLICE?

RCMP national headquarters says police agencies need judicial authorization to access or obtain information held by private-sector companies, including Ancestry.com and 23andMe, with the exception of special circumstances such as preventing bodily harm or death. However, it noted that open-source genealogy sites are public.

HOW ACCURATE IS THE PROCESS?

Moore says that in the Talbott case, she was especially confident because there was only one son who would carry the mix of DNA she was looking for. “The only caveat would be if there was another brother put up for adoption.” Armentrout says the evidence Parabon NanoLabs provides police is “very solid,” backed by genetic genealogy and other sources.