Do police have access to your DNA? What to know about investigative genetic genealogy

WEST PALM BEACH — You joined a genealogy site to connect with relatives but had them arrested for murder instead.

Such is reality for a growing number of people thanks to the rise of investigative genetic genealogy, which led to the arrest of the so-called Golden State Killer in 2018 and countless others since.

Police have used criminal genetic databases for decades, but sites like and 23andMe revolutionized the industry by allowing anyone to make their genetic material public. Law enforcement can access genealogists' online DNA profiles under certain circumstances, paving the way for breaks in decades-old crime — and renewed concerns over privacy.

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Some genealogy sites are more private than others.

Police can't access the databases of direct-to-consumer DNA testing giants AncestryDNA and 23andMe without getting a court order from a judge first. Most turn instead to GEDmatch or FamilyTreeDNA — the two genealogy sites that don’t require a warrant to access the data.

Both began as free, user-sourced tools for ancestry buffs years before the emergence of investigative genetic genealogy. People who had their DNA analyzed by private companies could make their genetic profiles public by uploading them to FamilyTreeDNA or GEDmatch, broadening their search for relatives.

Each site amassed more than 1 million users’ DNA profiles this way by the time detectives began combing it for relatives of unidentified perpetrators.

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Their privacy policies have shifted in the years since. Currently, police can see the only the names of relatives who have opted in to being seen — or in the case of FamilyTreeDNA, those who have not opted out. Thierry Bernard, the CEO of GEDmatch’s parent company Qiagen, said in January that about 70% of the GEDmatch database’s 1.8 million profiles are viewable to police.

Most white Americans can be identified through the DNA of someone else already.

Unless someone's immediate family is obsessed with its ancestry, it's unlikely police would find many of their first or second cousins in the GEDmatch database — but they could get hundreds of third cousins. That's enough to start building out a family tree.

A study published in the journal Science found in 2018 that 60% of Americans of European descent could be found through the DNA of a third cousin. GEDmatch encompassed about 0.5% of the U.S. adult population at the time of the study — once the figure rises to 2%, lead researcher Yaniv Erlich said more than 90% of people of European descent can be found in this way.

“People can be identified in ways now that we never would have imagined even a couple of years ago,” said Amy McGuire, a Palm Beach Gardens native and biomedical ethics professor at the Baylor College of Medicine in Texas. “If somebody really, really wants to try to identify you, I think they can. Or they will be able to eventually.”

Never had your genes tested? The DNA you leave behind is fair game for police.

Humans shed about 30,000 skin cells an hour — as much as 100 pounds worth of genetic material over a lifetime.

With the right analysis, the DNA contained in each cell can reveal deeply sensitive information about a person: what they look like, who their parents are, what their lineage is, what health conditions they may be predisposed to.

“You’re leaving it behind everywhere you go,” said Tiffany Roy, a forensic analyst from West Palm Beach. “Things you touch, things you drink from — and you're not even thinking about it.”

It's not an intentional discard, she said, but a biological one, and it comes into play at the tail end of an investigation. Once detectives have homed in on a person of interest, they’ll collect a DNA sample through something discarded, like a soda can, and confirm whether it matches the crime-scene sample. Detectives don't need a warrant to do this.

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Detectives use genetic genealogy for more than murders and cold cases.

Though it's known mostly for helping solve cold cases, investigative genetic genealogy is used in ones that are still hot, like the murder of four Idaho University students in December. Police found DNA on a knife sheath left at the crime scene and used investigative genetic genealogy to identify Bryan Kohberger as a suspect.

The other, less talked about way detectives use investigative genetic genealogy is to identify human remains. Identifying Baby Does and arresting their mothers — many of whom said they didn't know they were pregnant, or who lacked access to health care and social services at the time of the birth — intersects both applications, McGuire said, and it's among the most debated uses of investigative genetic genealogy.

"Should law enforcement, years later, be prosecuting a mother who's gone on to have a family and live a productive life, and is not a threat to society?” she asked.

Buyer beware: Little state and federal regulation protects your DNA.

The safeguards that keep police from misusing criminal genetic databases aren’t in place for commercial ones.

Christopher Slobogin, director of Vanderbilt Law School’s Criminal Justice Program, said people lose all expectation of privacy over their property once they give it to a third party — including their DNA. With no federal oversight, user confidentiality is left to the discretion of the database owners and operators.

"Lawmakers should be stepping in and just drawing some very firm lines about what is and is not permissible, and what the rules should be," said Nate Wessler, deputy project director with the American Civil Liberties Union.

Restricting police access to familial searches might make some investigations more challenging, Wessler said, but it's a trade-off lawmakers will likely be forced to consider as genetic databases, and their use by police, grow.

Hannah Phillips is a journalist covering public safety and criminal justice at The Palm Beach Post. You can reach her at

This article originally appeared on Palm Beach Post: Police are using genealogy sites to solve crime. Here's what to know.