Investigators hunting for the Golden State Killer turned to searching genetic websites in 2017 but misidentified a man as a potential suspect.
A year later, after using a similar technique, they are confident they have caught the serial rapist and killer who eluded capture for four decades.
In March 2017, an Oregon City police officer, working at the request of investigators in California, convinced a judge to order a 73-year-old man in a nursing home to provide a DNA sample.
Court documents obtained by The Associated Press said detectives used a genetic profile based on DNA from crime scenes linked to the serial killer and compared it to information on a free online genealogical site.
Investigators cited a rare genetic marker, which the Oregon man shared with the killer, to get the judge to issue the order.
The Oregon City man is in extremely poor health in a rehabilitation facility and was unable to answer questions on Friday.
His daughter said his family was not aware that authorities took a DNA sample from him while he was lying in bed at the rehabilitation centre until she was contacted by the FBI in April 2017.
She was asked to help expand the family’s genetic tree in the search for suspects.
The woman, an amateur genealogist, cooperated but ultimately investigators determined none of her relatives were viable suspects, she said.
“I don’t like that they thought that my dad was the bad guy, but the truth is they were able to rule out people in my dad’s (family) tree,” she said. “They didn’t have to look at those people anymore.”
“I mean, they go from California to Oregon to get my dad’s DNA? They clearly thought he was the bad guy,” she said. “I think DNA is amazing and if you’ve done something wrong you don’t deserve to be protected.”
Ultimately investigators turned to a different genealogical site and arrested a man now accused of being one of California’s most feared and elusive serial killers.
On Friday, Joseph James DeAngelo appeared in court to face murder charges.
Handcuffed to a wheelchair in orange jail scrubs, the 72-year-old looked dazed and spoke in a faint voice to acknowledge he was represented by a public defender. He did not enter a plea.
DeAngelo, a former police officer, has been charged with eight counts of murder and additional charges are expected, authorities said.
“We have the law to suggest that he is innocent until he’s proven guilty,” said his lawyer, Diane Howard.
Investigators arrested DeAngelo on Tuesday after matching crime-scene DNA with genetic material stored in an online database by a distant relative.
They relied on a different website than for the Oregon search and did not seek a warrant for his DNA.
Instead, they waited for him to discard items and swabbed them for DNA, which proved a conclusive match to evidence from crimes more than 30 years ago, they said.
The co-founder of the genealogy website used by authorities to help identify DeAngelo said he had no idea it was used by law enforcement.
The free genealogy website, which pools DNA profiles that people upload and share publicly to find relatives, said it has always informed users its database can be used for other purposes.
But co-founder Curtis Rogers said the search was “done without our knowledge” and the company does not “hand out data”.
Officials did not need a court order to access GEDmatch’s large database of genetic blueprints, lead investigator Paul Holes told the Mercury News in San Jose, California.
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