Genealogical websites helped nab suspect
“This is the first time it’s been successful, and it’s on a gigantic case. This is fantastic.” Forensic DNA expert Greg Hampikian, on the use of genealogical websites
SACRAMENTO — Investigators broke open the longstagnant case of the prolific serial killer and rapist known as the Golden State Killer by mining DNA profiles collected by genealogical websites used by individuals to trace family heritage, the Sacramento County district attorney’s office said Thursday.
Law enforcement had long had a DNA profile of the suspected killer, which helped them connect murders and rapes across the state to the same unidentified man. But, the DNA profile did not match any contained in criminal databases that are used by law enforcement throughout the U.S. to link crimes to suspects.
The explosion in recent years of DNA heritage websites such as 23andMe and Ancestry.com provided investigators with another tool, although both of those companies said Thursday they were not involved in this case.
The genealogical sites, which were not revealed, linked the suspect’s DNA profile to a likely family member, two sources familiar with the case told The Chronicle, allowing investigators to build a pool of suspects and then narrow it down. They obtained a court order to compel the site to
work with them, one of the sources said.
Ultimately, detectives said they got what they had long awaited — a DNA match to Joseph James DeAngelo, an ex-cop living in Citrus Heights (Sacramento County). They followed him and collected an item he had discarded that they say contained his DNA.
DNA experts said the use of genealogical websites is a controversial and unorthodox method to solving crimes, one that could pose ethical questions if it involves a commercial company where users have an expectation of privacy.
There are also publicly available databases online that offer anyone the ability to upload and view DNA results to learn more about their family tree.
Investigators had been hesitant to reveal how they came to identify DeAngelo as the Golden State Killer or East Area Rapist, whose reign of terror included 12 slayings and 45 rapes in California from 1976 to 1986. The Sacramento County district attorney’s office confirmed that the use of genealogical websites narrowed their pool of suspects after news outlets, including The Chronicle, reported the method.
Sacramento Sheriff Scott Jones said a task force trying to solve the heinous crimes turned to “very innovative and emerging DNA technology that gave us a universe to look in.” DeAngelo had not been on detectives’ radar previously.
It’s possible, said New York University law Professor Erin Murphy, an expert in forensic evidence, that detectives might have been reluctant to tell the public how they identified a suspect because they know people are uneasy about the use of genealogical websites as crime-fighting tools. If a company turned over DNA information, Murphy said that would not be unprecedented, but also not without problems.
“There could be huge ethical issues there,” Murphy said.
One of the biggest genealogical companies, Ancestry.com, said the company has had no contact with law enforcement in the DeAngelo case. The company’s policy is to provide information only when compelled by court order or warrant, a spokeswoman said.
The company has received one search warrant in its history demanding that it identify a person based on a DNA sample. In that 2014 case, police searched a public DNA database owned by Ancestry.com using DNA collected at a homicide scene in Idaho and found a profile that matched 35 of 36 genetic markers, leading to the possibility that a family member of that person was their suspect. While the DNA profile was public, the name of the person who uploaded it was not, leading police to obtain a warrant for the identity.
In that case, police hit another dead end, ultimately clearing a man they suspected and saying that his family members were also not involved.
A spokesman for 23andMe, a genetic testing firm based in Mountain View, said the company was not contacted in the DeAngelo case.
It’s possible, Murphy said, that detectives used various publicly searchable genealogical websites, which she said eases privacy or ethical questions.
Detectives could have focused on the Y-STR — part of the male Y chromosome that is handed down paternally — to find a relative or find a likely last name, Murphy said. Combine that narrowed list with the likely age of a suspect and geography, and “that could give you a smaller list of names,” Murphy said.
Forensic DNA expert and biologist Greg Hampikian said genealogical websites have been used in missing-person cases, but mining them for criminal suspects is a novel approach that had yet to be successful.
“It’s been tried, but this is the first time it’s been successful, and it’s on a gigantic case,” said Hampikian, who consulted on the 2014 case in Idaho using information from Ancestry.com. “This is fantastic.”
Others said the privacy concerns raised by the case are weighty. Most testing companies don’t explicitly say in their privacy policy or terms of service that they’ll hand over customer information if police departments seek it. But they may not have a choice if ordered by a court to do so, experts said.
“A few (ancestry sites) will say, ‘We’ll protect your privacy in so far as we can go — unless the courts intervene,’ ” said Sheldon Krimsky, a professor at Tufts University who has written about bioethics and privacy, including a 2017 report on consumer privacy and DNA. “Most say, ‘We’ll do our best.’ ”
The use of a genealogical site is different from traditional familial searches using DNA — like the one that unmasked the Grim Sleeper. In that case, police linked Lonnie Franklin Jr. to the killings of 10 people over 25 years using a DNA sample from his son, whose genetic profile had been uploaded into a database of known criminals.
“The familial search process, the way it’s designed and the way it works, it gives you a father, son or full sibling,” said Rockne Harmon, a consultant to numerous law enforcement agencies on cold cases and a former Alameda County prosecutor.
California expanded its use of familial DNA 10 years ago, when then-Attorney General Jerry Brown allowed law enforcement agencies to receive notification when a partial DNA match — not just a full DNA match — was made in a case, which allowed detectives to link crimes through relatives. Familial searches are designed to produce only a close male relative, Harmon said, which usually results in one suspect, like in the case of the Grim Sleeper.
“It either picks out the right person or no one,” Harmon said. “Familiar searching has become far more commonplace, and it’s not as big of a deal anymore.”
That’s not the process law enforcement officers were describing when they unmasked their suspect Wednesday at a news conference outside the Sacramento district attorney’s crime lab. There, they described a flurry of activity over the past week as they closed in on DeAngelo.
DeAngelo’s name was known to investigators at least a month ago. Paul Holes, a cold-case investigator for the Contra Costa County district attorney’s office, said the list of potential suspects had been narrowed to roughly five men — DeAngelo among them. Still, DeAngelo wasn’t at the top of that list, Holes said, until DNA ruled out some of the other men.
Sacramento County sheriff ’s deputies began surveilling DeAngelo’s home and were able to obtain two “surreptitious samples” from him — meaning they waited for him to discard something with his DNA on it. Investigators got one sample a week before his arrest, but it was too weak, Holes said.
They went back and tested a second sample, which investigators said was a 100 percent match. DeAngelo was then arrested. According to Sacramento County Sheriff Scott Jones, he was “very surprised.”