Could Your DNA Solve a Murder?

• Author: Bubar, Joe
• Position: NATIONAL

As more people hand over their DNA to genealogy services to uncover their ancestry, police are using this genetic info to solve crimes. It may help keep us safer, but is it a violation of privacy?

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 heinous crimes. As the suspect, a 72-year-old retired police officer named Joseph James DeAngelo, awaits trial, many people across California are breathing a sigh of relief.

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

Genealogy services have become increasingly popular in recent years. More than 15 million people in the U.S. have offered up their DNA--a cheek swab or some saliva in a test tube--to services such as Ancestry.com and 23andMe in pursuit of answers about their heritage or to gauge their risk for certain medical conditions. In exchange for a genetic fingerprint, individuals may find a birth parent, long-lost cousins, perhaps even 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?"

Cracking Cold Cases

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," p. 16).

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.

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.

Catching a Murderer

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, which 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--to look for records, newspaper articles, social media accounts, and anything else that can help them build a family tree. They then look for anyone in that family tree whose age and location fit the crime.

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

An Invasion of Privacy?

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...