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New ground breaking forensic technique could help gardaí crack cold cases

The process of ‘investigative genealogy’ could help An Garda Siochana solve cold cases, Paul Holes believes
Paul Holes (Picture Celadon Books)

Paul Holes (Picture Celadon Books)

Clodagh Meaney

The pioneer of a ground-breaking forensic technique used to solve cold cases across the United States says he believe the method that could help gardaí.

Paul Holes, who appears on Episode 114 of Crime World was the first investigator to use genetic genealogy to solve a cold case.

The Contra Costa County detective began working on the case of the Golden State Killer in 1994 and continued to do so until the day he retired in 2018.

Using the innovative technique, the serial rapist and killer who terrorised California between 1974 and 1986 was caught in 2018.

Unmasked as 72-year-old Joseph James DeAngelo, he was a former police officer who committed at least 13 murders, 50 rapes, and 120 burglaries during his criminal career.

Speaking to Crime World, Paul Holes, who has a background in forensic science, explained that the method of tracking down a suspect using genetic genealogy can help prevent authorities pursuing false leads.

“That’s what I want to get out there, if [Irish] legislators or lawmakers are considering whether or not they want to expand the use of ‘Investigative [Genetic] Genealogy’.”

To use the technique, the investigator must first have a sample of DNA belonging to the person they are looking to get a name for.

“With genetic genealogy, first you have to have a DNA profile of your offender, or the person you’re looking for. With the Golden State Killer, he had left DNA behind.”

Holes, who recently released his biography ‘Unmasked’, had the idea to use DNA to build family trees in a bid to seek out a suspect in the case as he kept hitting dead ends.

Explaining the process of genetic genealogy, he said: “Taking your DNA sample you get a special DNA type profile, not a law enforcement style profile, but a profile used by ancestry websites, in order to link relatives together in their database.”

Once the profile is created, ancestry websites can be searched for any matches that share DNA with the person you’re looking for.

“Of course there's a lot of privacy issues that people are concerned about, but I have to really emphasise that I, as a law enforcement officer, during this process, never had access to anyone’s genetic information in these databases.”

“I am no different than a typical user of an ancestry website, getting an email saying ‘we found a third cousin’.”

“All it does is give me this random list of say 10 third cousins of the Golden State Killer, at this point it is then pure genealogy work, anybody can do this.”

“You just start building family trees of the people in the list,” Holes explained.

“The purpose of building these trees is to find at least two people on the list where you can say ‘these two people share common ancestors back in time’.”

“Once you have those you build the family tree up to the present time, but you need to have all descendants.”

“It’s a difficult and time consuming process but once you get into it you see who on this list circumstantially is the person we can go and get a DNA sample from.”

Gardaí in Ireland have not yet utilised genetic genealogy on the same scale as investigators in the United States to solve a case.

However, experts believe it may be useful to solve the Kerry babies case, as well as to identify the 796 babies found buried at the Tuam Mother and Baby Home.


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