By Sarah Souli


Between 1974 and 1986, residents in California were terrorized by an unknown assailant dubbed the Golden State Killer. He was prolific in his evilness, committing 13 murders, over 50 rapes, and more than 100 burglaries. His M.O. was horrific: he would conduct extensive reconnaissance in homes, staking out all the entry and exit points, breaking locks, removing any guns or weapons, and memorizing the residents’ daily patterns. He targeted women and children, but liked couples — he would separate them and rape the woman for hours. Men were subjected to a special brand of psychological torture, as the GSK would stack plates on their back, threatening to kill everyone in the house if one of the plates rattled.

For decades, police, investigators, and private sleuth-citizens were unable to discover the identity of the GSK. Dozens of suspects were cleared with alibis or DNA evidence; each new clue seemed only to lead to another frustrating dead end. Then on April 24, 2018, the Sacramento County Sheriff’s Department made a startling announcement: they had caught the Golden State Killer.

At 72 years old, and sporting a blank, dazed expression, Joseph DeAngelo didn’t look — at least from his mugshot — like a killer. He looked more like a crotchety old man, the kind that yells at children to get off his lawn. But DeAngelo’s DNA conclusively matched that of rape kits done in the 1970s and 1980s. Everyone wanted to know, after nearly 40 years, how police had finally caught DeAngelo. Stake-out? High-speed chase? Confession? Fingerprints?

Turns out police found DeAngelo using a genealogy website.

One in 25 Americans have voluntarily submitted their DNA to companies like Ancestry.com, 23andMe, MyHeritage, and FamilyDNA. In 2017, the number of people who ordered kits to test their saliva doubled, and now exceeds 12 million individuals. Apparently we love searching for our ancestors, connecting with distant cousins, and getting a better understanding of our cultural and ethnic heritage. Genealogy is the second most popular hobby in the U.S. after gardening, and the second most visited category of websites after pornography.

When we send our DNA to private companies for testing, we’re not necessarily thinking of the larger ramifications. It’s about your experience, your history, your family tree, a personal quest for information. Two months after sending in a spit-swaddled kit to a genealogy company, results are sent back via post; after finding out what percentage of your DNA is Neanderthal or Asian or European, most people forget about the matter. But the companies don’t.

“The companies offering these tests largely make their money not from doing the tests, but from selling the genetic information to other companies interested in having access to large genetic databases,” Sheldon Krimsky, the Lenore Stern Professor of Humanities and Social Sciences at Tufts University and author of Genetic Justice told TuftsNow in January 2018. “Almost 50 percent of the firms that sell you your ancestry information turn around and sell your genetic information to some other company,”

Informed consent rules differ between companies, though in general consumers are required to give their consent for their DNA to be shared with third-parties, or for their DNA to be used in research projects conducted by academic, nonprofit, or industry organizations. 23andMe reports that, surprisingly, 80 percent of consumers voluntarily consent to sharing their personal data. Asking for consent is good for trust-building between consumers and a faceless corporation, but that trust is often just an illusion.

The Federal Trade Commission is currently investigating 23AndMe and Ancestry.com over their policies with third-party sharing: If, through some altruistic motivation you consent to Ancestry.com’s Human Diversity Project, your biological sample “can be collected and used for research consistent with the Purpose until the Project is completed or ends (which may be many years from now).” You can withdraw your consent at any point, but your data will remain in the system — a legal nullification of any consent.

DeAngelo was found using GEDMatch, a website that pools user-uploaded genetic profiles from other genealogy websites. GEDMatch exists “to provide DNA and genealogy tools for comparison and research services” and has an open-source database of 650,000 genetically connected profiles. DeAngelo, who evaded capture for decades, was meticulous in his crime scenes and certainly did not upload his DNA to a website in the hopes of uncovering his ancestry. But a third cousin of his did.

Police created a genetic profile for the GSK suspect using DNA samples from old crime scenes (samples that had never been conclusively identified). By running that DNA through GEDMatch, they were able to get a pool of relatives who shared parts of the same genetic material. Additional factors, like age, gender, and location, were used to rule out suspects. When police settled on DeAngelo, they staked out his home and obtained his DNA sample from a surreptitious swipe of his door handle, and a piece of trash.

Police were lauded for their detective work, which included four months of genealogical digging, and both survivors and the families of the victims expressed their profound relief that their nightmare was finally over. But amidst the celebration there was concern that law enforcement had crossed a legal line around privacy.

“The privacy concerns raised by the Golden State Killer investigation don’t disappear just because GEDmatch, the genealogical database investigators reportedly used, was a public site. In fact, investigators’ decision to upload a detailed genetic profile generated from crime-scene DNA to a public website likely violated the alleged perpetrator’s privacy rights,” Vera Eidelman of the American Civil Liberties Union (ACLU) wrote in an op-ed in the Washington Post. “Even if DeAngelo is found guilty of the crimes he is accused of, penalties for such crimes do not typically entail releasing a person’s entire genetic makeup. People may not be so troubled by such an intrusion when it comes to a serial killer, but imagine the implications of using this technique for shoplifters or trespassers.”

But genealogical testing is “not something you’re going to do on a burglary or a petty theft,” said Paul Holes, a cold-case detective who helped catch DeAngelo. “It is going to be on your major, major homicide cases because it is so manpower-intensive. It is tough, tough work.”

There are countless imagined, dystopian futures in pop culture and science fiction wherein the use of secretly gathered DNA marks the demise of egalitarianism. It’s not a stretch to imagine this happening today — but the biggest irony is that we are the ones willingly, and even eagerly, giving up our own data.



Sarah is a freelance journalist based in Athens. Her work has been featured in The New Republic, The Economist, The Guardian, Vice, and others. She is a contributing writer to the Journal of Beautiful Business.