DNA sleuth CeCe Moore recalls the moment that the pieces came together, in May, in the hunt for her first suspected killer – the man now thought to be responsible for the brutal 1987 murders of a young Canadian couple on a trip to Seattle. While Moore is used to uncovering secrets – she’s helped hundreds of adult adoptees to identify their biological parents – finding someone who might be guilty of murder was shocking. “It is hard to even put into words. It was a very surreal feeling,” she says. Moore, a genetic genealogist known in the US as an expert on the PBS television series Finding Your Roots, runs DNA Detectives, a Facebook group of 100,000-plus members, which helps people find their biological parents.

Since May, she has also headed a forensic genealogy unit at the DNA tech company Parabon, which helps police find perpetrators of violent crimes – mostly unsolved murders and rape. She uses a controversial method called genetic, or forensic, genealogy that is becoming indispensable to police forces while raising legal and ethical questions. To date, the work of Moore and her team has led to identifications in 21 US cases and she says that there will be more soon (no case has yet come to trial, so all those identified are for now suspects only).

The technique entails uploading a crime-scene DNA profile to a public-access genealogy database called GEDmatch. The database allows people to trace relatives by uploading DNA tests carried out by companies such as 23andMe and Ancestry and holds the DNA profiles of about 1.2 million people.

Major genealogy data-holders, including the consumer genetic testing companies, may give up information to law enforcement if subpoenaed, but GEDmatch is the only one that permits open searching by law enforcement officials for the purpose of solving violent crimes, which the site defines as homicide or sexual assault.

Moore looks for partial DNA matches between the crime scene DNA profile and other GEDmatch profiles to find relatives, with typically second or third cousins – of which we have on average about 30 and nearly 200 respectively – needed for a good chance of success. Family trees are then built backwards to shared ancestors, and forwards using birth, death and marriage records and public Facebook pages, to identify potential perpetrators, who then have DNA samples taken by law enforcement officials to see whether their DNA matches that found at the crime scene. Parabon charges police $1,500 (£1,200) for the DNA processing and genetic genealogy assessment to determine if the case is “workable”.

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The partial matching of crime-scene DNA from an unknown person to that of their relatives isn’t new, says Mark Jobling, a professor of genetics at the University of Leicester, who co-directs its Alec Jeffreys Forensic Genomics Unit. “Familial search”, using police DNA databases, was pioneered in the UK in 2004. But searching GEDmatch is potentially more effective because the DNA profiles in it are based on newer DNA technology that provides more points of comparison, making it possible to find more distant relatives.

Police databases, in contrast, can’t go much beyond detecting immediate family members such as parents, siblings, and children. The older technology has advantages, however – the profiles are cheaper to create and don’t need much, or as good quality, DNA.

One recent study puts the chances that a search in GEDmatch will result in a match with a third cousin or closer at about 60%, where the search is for US individuals of European descent. (Unlike police databases, where black people are over-represented, in GEDmatch the bias runs the opposite way.) The author of the study, Yaniv Erlich, a computer and genetics expert who has taken leave from Columbia University to work for the genealogy company MyHeritage, expects that it will take only a few years until almost all those in the US with European ancestry achieve such a match. Though of course to find a perpetrator you also need the genealogy and descendancy work – which is where Moore’s experience comes in. “That additional step is not trivial, and it is not automatable at the moment,” says Jobling.

Facebook Twitter Pinterest Former police officer Joseph James DeAngelo, who is charged with being the ‘Golden State Killer’. Photograph: Jose Luis Villegas/AP

The first case where genetic genealogy yielded a result for police was April 2018, with the arrest of a former police officer Joseph James DeAngelo, the alleged “Golden State killer”, who was one of the most prolific predators in US history, committing rape and murder across California, beginning 40 years ago. It was not the work of Moore but of another genetic genealogist working anonymously (later revealed to be Barbara Rae-Venter, the ex-wife of US scientist Craig Venter), that helped lead to his arrest – a DNA profile was created from an old DNA sample and uploaded to GEDMatch using a spoof name.

Afterwards, the co-founder of GEDmatch, Curtis Rogers, barely slept for two weeks trying to decide whether to bar or embrace law enforcement’s use of the site. “I never really gave a thought about law enforcement until it hit me over the head,” he says.

He decided, in the end, to allow police use for violent crimes but to make site-users aware that their data might be used for this purpose. It has always been possible for people to remove their data from GEDMatch, he says. After the terms of service were updated, there was a small exodus, but it settled down. “We get love letters thanking us for doing what we do,” Rogers says.

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His decision also freed Moore to use the technique to identify perpetrators. Before GEDmatch’s terms of service were updated, she considered it personally unethical, because she had spent years encouraging people to participate in genetic genealogy by getting tested and uploading to the service. “I didn’t feel like I could then turn around and use that very data for a purpose [people] weren’t aware of,” she says.

It took just a weekend for Moore to identify her first suspected killer – William Earl Talbott II. She “works” her cases intensively – on the sofa in her pyjamas, barely sleeping, with her husband bringing her dinner. Parabon uploaded the crime-scene DNA profile to GEDmatch on a Friday and got a match list the next morning – ranked by those in the database that shared the most DNA with the suspect. She deduced that he had two second cousins – from different branches of the family tree – in the database (though it later turned out one was a half first cousin once removed, which is genetically equivalent). Knowing second cousins share great grandparents, Moore built family trees back to each set. Then she flipped the method and began trying to find their descendants.

It was an obituary that gave Moore what she calls her “triangulation” – where the two family trees converged. A woman from one side of the tree had the married surname of the other side of the tree. Moore looked up the public marriage record and went on to find that the couple had had four children, only one of whom was male. “It was pointing right at [him],” she says. She spent the rest of the weekend firming up her theory. “I don’t want to hand the name over unless I am really sure,” she says. It included discovering that he lived close to where the bodies were found. By Monday she was certain. She gave the name to detectives, who followed him and got a sample of his DNA from a discarded paper cup. It matched that of the crime-scene DNA and he was arrested and charged.

Facebook Twitter Pinterest William Earl Talbott II, who was identified by Moore and now awaits trial for a double murder in 1987. Photograph: Andy Bronson/The Herald, AP

Moore estimates about half of the cases she gets are “workable” – meaning that they have strong enough matches to proceed. They then divide roughly into three: those resolvable quickly, those that will take time, and those that need more than genetic genealogy alone to solve but could be done with in depth police collaboration. She notes that this can change, because new people upload to GEDmatch daily. And while Moore has mostly worked decades-old unsolved cases to date, where she would like to help more is in shortening “careers” of active murderers and rapists.“ There is no reason why we can’t address these crimes as they are happening,” she says.

The use of genealogy databases to solve violent crimes appears to have high public support. A survey of nearly 1,600 people following the Golden State Killer case showed that, in such cases, nearly 80% of respondents supported police searches of websites that identify genetic relatives – but there are concerns about the technique.

One is how to protect the privacy of people who have not chosen to upload their DNA to GEDmatch. This is because the technique requires identifying relatives of people who have uploaded their DNA – relatives who have not themselves voluntarily shared any information at all. “It potentially affects everyone and not just those who are in the GEDmatch database,” says Debbie Kennett, a UK-based genealogist and author who has also been outspoken on the ethics of genetic genealogy.



Amy McGuire, a professor of biomedical ethics at Baylor College of Medicine in Texas, says that it is an open legal question. Should law enforcement, in pursuit of justice, be allowed to go on what is “essentially a fishing expedition” to try to identify somebody who might be a relative of the potential suspect without a warrant and without reasonable cause, or should their privacy be protected?

Privacy also comes into play in the case of false leads – where innocent people are investigated, and surveilled often for several days so their DNA can be surreptitiously collected. Before the Golden State Killer was identified another person was identified based on the technique, but ultimately not confirmed as the suspect. Moore says that she and her team have the expertise to narrow things down significantly, but both she and Kennett worry that the lack of requirement for formal qualifications, and recent publicity about the technique, could attract people who are not so skilled.

Moore is now waiting to see if genetic genealogy stands up to scrutiny in court, and wins its first convictions. In the meantime, observers such as Kennett hope that the technique will be regulated, bringing it into line with searches of police DNA databases. Erlich would like to see some security built into the system to reduce the chance of GEDmatch being used for nefarious purposes.

Moore’s hope is that because of her work people will find it much harder to get away with these violent crimes – and that maybe, for someone out there in the heat of the moment, knowledge of her work will act as a deterrent. “If even one life is saved because of that, it would all be worth it,” she says.

Genetic genealogy – coming to the UK?

While genetic genealogy techniques don’t appear to have been applied by UK law enforcement officials yet in any British cases, there is “interest and enthusiasm,” says Mark Jobling, a professor of genetics at the University of Leicester. “It probably is only a matter of time.”

Parabon, a DNA tech company based in the US, says it has had inquiries from the UK but has not taken any cases. The Metropolitan police said it was aware of Parabon and public-access genealogy database GEDmatch, and “would be keen to utilise such techniques as and when they are deemed appropriate”. The chances of a British suspect matching to relatives on GEDmatch is lower – because most people on the GEDmatch database live in the US (followed by Canada, the UK and Australia). That could change, however, as more people in the UK undergo consumer genetic testing and upload their results.