Could Your DNA Solve a Murder?

For more than 40 years, the Golden State Killer had been on the loose. Police had linked the notorious serial killer to a dozen murders and more than 50 rapes across California from 1976 to ’86. Yet he’d eluded all their attempts to find him. The case had seemingly gone cold.

But investigators say they’ve finally cracked it. Last spring, they arrested a man in a Sacramento suburb who they think committed these terrible crimes. The suspect is a 72-year-old retired police officer named Joseph James DeAngelo. As he awaits trial, many people across California are breathing a sigh of relief.

But the way the police found DeAngelo has many civil liberties experts concerned. That’s because police tracked him down using a public genealogy database called GEDmatch.

Genealogy services have become very popular in recent years. More than 15 million people in the U.S. have offered up their DNA to services such as Ancestry.com and 23andMe. It’s been as simple as a cheek swab or some saliva in a test tube. Some people have used these services to find answers about their heritage. Others want to check their risk for certain medical conditions. In exchange for a genetic fingerprint, individuals may find a birth parent or long-lost cousins. They might even find a link to George Washington or Queen Victoria.

With more and more people signing up for these services, though, many in law enforcement see another use for them: as huge databases of DNA, which they can compare with DNA from crime scenes to help them catch criminals.

The question is whether police should be allowed to access genealogy sites, which contain highly sensitive information about their customers and their families. 

“This is really tough,” says Malia Fullerton, an ethicist at the University of Washington who studies DNA forensics, speaking about DeAngelo’s arrest. “He was a horrible man and it is good that he was identified, but does the end justify the means?”

More and more people are signing up for these services. Many in law enforcement see another use for them. They view them as huge databases of DNA. In other words, they want to use these sites to compare DNA from crime scenes to help them catch criminals.

These genealogy sites contain highly sensitive information about their customers and their families. The question is whether police should be allowed to access them.

“This is really tough,” says Malia Fullerton, an ethicist at the University of Washington who studies DNA forensics, speaking about DeAngelo’s arrest. “He was a horrible man and it is good that he was identified, but does the end justify the means?”

Your DNA is like a blueprint to your body. In these microscopic strands of genetic material lies an enormous amount of information not just about you, but also about your parents, siblings, and your distant relatives. That’s why genealogy services are able to tell people so much about their family history simply by analyzing their DNA (see “A Road Map to Your Ancestors,” below).

That’s also why police are increasingly turning to these services as powerful crime-solving tools. Since DeAngelo’s arrest, police have used GEDmatch to identify about two dozen other suspects in murder and sexual assault cases. Many of them were gruesome killings that had gone unsolved for decades, like the case of the 12-year-old girl murdered in 1986 after being kidnapped while playing in a park near her home in Washington State; the 8-year-old girl who was found dead in a ditch in India in 1988; and the 25-year-old Pennsylvania teacher beaten and strangled to death in 1992.

Your DNA is like a blueprint to your body. In these microscopic strands of genetic material lies an enormous amount of information. And it’s not all just about you. There’s also info about your parents, siblings, and your distant relatives. That’s why genealogy services are able to tell people so much about their family history. All that’s needed is an analysis of their DNA (see “A Road Map to Your Ancestors,” below).

That’s also why police are increasingly turning to these services as powerful crime-solving tools. Since DeAngelo’s arrest, police have used GEDmatch to identify about two dozen other suspects in murder and sexual assault cases. Many of them were gruesome killings that had gone unsolved for decades. That includes the case of the 12-year-old girl murdered in 1986 after being kidnapped while playing in a park near her home in Washington State; the 8-year-old girl who was found dead in a ditch in India in 1988; and the 25-year-old Pennsylvania teacher beaten and strangled to death in 1992.

Some genealogy services, including the popular 23andMe and Ancestry.com, have policies against handing over customer information to law enforcement, but police can access these databases by getting permission from a court. GEDmatch is slightly different. It’s a public database to which anyone can upload their genetic code to look for family members—often after they’ve gotten their results from other services, like 23andMe. GEDmatch allows police to access the database.

Some genealogy services have policies against handing over customer information to law enforcement. The popular 23andMe and Ancestry.com have these type of limits in place. But police can access these databases by getting permission from a court. GEDmatch is slightly different. It’s a public database to which anyone can upload their genetic code to look for family members. These users have often gotten their results from other services, like 23andMe. GEDmatch allows police to access the database.

How do investigators use a genealogy database to catch a killer? First, they upload a murderer’s DNA that they’ve collected from a crime scene. They look for anyone on the database who shares some of the same DNA. That would mean that person is related to the killer. Once they’ve found a relative, police then search that person’s name and a few simple facts, such as a birthdate and birthplace. This helps them track down records, newspaper articles, social media accounts, and anything else they can use to build a family tree. They then look for anyone in that family tree whose age and location fit the crime.

It’s a tough process, but eventually a skilled genetic detective may be able to find a murderer, even one who’s been hiding for decades.

That’s how police tracked down DeAngelo. They created a fake profile on GEDmatch and uploaded a sample of the Golden State Killer’s DNA found at a crime scene years ago. The results connected them to DeAngelo’s third cousin, who had at one time signed up for the service. Following the family tree led investigators to their suspect.

“For law enforcement: Bravo, bravo, bravo,” Bruce Harrington, whose brother and sister-in-law were murdered by the Golden State Killer, said shortly after DeAngelo’s arrest. “Today is also a reaffirmation in the power and the public safety that is associated with forensic DNA technology.”

Despite the success in finding DeAngelo, privacy experts say these tactics are concerning for a few reasons. For one, when people upload their DNA to one of these sites, they aren’t exposing just themselves to possible police investigations. They’re also exposing anyone who shares their DNA. 

As Steve Mercer, a chief attorney for the Maryland Office of the Public Defender, told the Associated Press: “People who submit DNA for ancestors testing are unwittingly becoming genetic informants on their innocent family.”

That’s how police tracked down DeAngelo. They created a fake profile on GEDmatch and uploaded a sample of the Golden State Killer’s DNA found at a crime scene years ago. The results connected them to DeAngelo’s third cousin, who had at one time signed up for the service. Following the family tree led investigators to their suspect.

“For law enforcement: Bravo, bravo, bravo,” said Bruce Harrington, whose brother and sister-in-law were murdered by the Golden State Killer, shortly after DeAngelo’s arrest. “Today is also a reaffirmation in the power and the public safety that is associated with forensic DNA technology.”

Despite the success in finding DeAngelo, privacy experts say these tactics are concerning for a few reasons. For one, when people upload their DNA to one of these sites, they aren’t exposing just themselves to possible police investigations. They’re also exposing anyone who shares their DNA. 

As Steve Mercer, a chief attorney for the Maryland Office of the Public Defender, told the Associated Press: “People who submit DNA for ancestors testing are unwittingly becoming genetic informants on their innocent family.”

In fact, the police may even be able to find you through one of these databases—just because a distant cousin you’ve never even met took a DNA test. A recent study published in the journal Science found that 60 percent of white Americans—the primary group using these sites—can be identified through such databases, regardless of whether they’ve joined one themselves. Within two or three years, 90 percent of Americans of European descent will be identifiable from their DNA.

The science-fiction future, in which everyone is known whether or not they want to be, “is not the distant future,” says Yaniv Erlich, the lead author of the study. “It’s the near future.”

Another concern privacy experts have is that the police may be uploading the DNA of someone to a public website without that person’s consent. 

“Perhaps we think that’s OK for a serial killer, but what if this starts getting used to solve shoplifting crimes or trespassing crimes?” says Vera Eidelman, a lawyer at the American Civil Liberties Union. “Do we really think that it’s OK for all of this private genetic information to be available online?”

In fact, the police may even be able to find you through one of these databases. And that’s just because a distant cousin you’ve never even met took a DNA test. White Americans are the primary group using these sites. A recent study published in the journal Science found that 60 percent of white Americans can be identified through such databases. And that’s regardless of whether they’ve joined one themselves. Within two or three years, 90 percent of Americans of European descent will be identifiable from their DNA.

The science-fiction future, in which everyone is known whether or not they want to be, “is not the distant future,” says Yaniv Erlich, the lead author of the study. “It’s the near future.”

Another concern privacy experts have is that the police may be uploading the DNA of someone to a public website without that person’s consent. 

“Perhaps we think that’s OK for a serial killer, but what if this starts getting used to solve shoplifting crimes or trespassing crimes?” says Vera Eidelman, a lawyer at the American Civil Liberties Union. “Do we really think that it’s OK for all of this private genetic information to be available online?”

Researchers at Baylor College of Medicine, in Houston, recently asked the public what they thought. According to their survey, 91 percent of people say law enforcement should be able to search genealogical websites to try to solve violent crimes. But less than half of Americans think police should search these sites to investigate nonviolent crimes.

At some point, legal experts say, the courts may have to weigh in on these privacy questions. The Fourth Amendment to the Constitution prohibits “unreasonable searches and seizures,” guaranteeing Americans some privacy rights. 

Researchers at Baylor College of Medicine, in Houston, recently asked the public what they thought. According to their survey, 91 percent of people say law enforcement should be able to search genealogical websites to try to solve violent crimes. But less than half of Americans think police should search these sites to investigate nonviolent crimes.

At some point, legal experts say, the courts may have to weigh in on these privacy questions. The Fourth Amendment to the Constitution prohibits “unreasonable searches and seizures.” That guarantees Americans some privacy rights. 

But when the Framers wrote the Bill of Rights in the late 1700s, they had someone’s home or property in mind. They couldn’t have imagined considering someone’s genetic makeup. The courts may be asked to decide how to apply that 18th-century document to our 21st-century science.

“People are very interested in obtaining and sharing their genetic data to learn more about themselves,” says Daniel MacArthur, a researcher at Massachusetts General Hospital. “It’s a natural human instinct. But legislative protection is required to ensure that it’s not used for nefarious purposes.”

With reporting by Gina Kolata and Heather Murphy of The Times.

With reporting by Gina Kolata and Heather Murphy of The Times.