A popular DNA ancestry platform that recently confessed to sharing people’s genetic data with the FBI is now asking customers to assist in the hunt for killers and criminals.

“If you are one of the millions of people who have taken a DNA test, your help can provide the missing link,” Edward Smart, father of kidnapping victim Elizabeth Smart, says in a new ad for Family Tree DNA that appears on the company’s webpage for potential customers.

Family Tree DNA is one of the country’s largest commercial genetic testing companies, with a database of more than two million profiles. Some of this data belongs to people who have purchased one of the company’s own tests—a cheek swab—while some has been uploaded in raw form by users from competing platforms, such as 23andMe or Ancestry.

In January, BuzzFeed News exposed the company’s quiet deal with the FBI, brokered in 2018, which gave agents search access to its huge DNA database. According to the New York Times, under the agreement the FBI could upload DNA to the platform and receive results, and Family Tree DNA’s parent company—Houston-based Gene by Gene—agreed to process FBI samples in its lab.

The terms of the deal mirrored a forensic technique used to arrest Golden State Killer suspect Joseph James DeAngelo last April. The California serial killer also known as EARONS (East Area Rapist/Original Night Stalker) is accused of more than 50 rapes and 12 murders throughout the 1970s and 1980s.

In that case, investigators converted old crime scene DNA into a genetic profile and uploaded it to GEDmatch, a public genealogy database that allows users to find relatives with whom they share DNA. After locating familial hits, investigators searched their relatives for someone who fit the Golden State Killer’s description. Eventually, they landed on 72-year-old DeAngelo who was arrested at his Sacramento home.

The technique is now being used on a number of cold cases. In San Diego, where the Family Tree DNA ad is slated to air on television according to MIT Technology Review, police recently tapped a genealogy database to identify a suspect in the brutal 1979 murder of Barbara Becker.

“The genealogy community has the ability to crowdsource crime solving,” Bennett Greenspan, president and CEO of Family Tree DNA, said of the new ad in a press release, as per MIT Technology Review.

The creeping prevalence of law enforcement on consumer DNA ancestry platforms is controversial, and Greenspan apologized to customers in February for not disclosing the company’s deal with the FBI.

GEDmatch, which is public and can be used anonymously, pushed back on claims that it collaborated with police in the Golden State Killer investigation.

“Although we were not approached by law enforcement or anyone else about this case or about the DNA, it has always been GEDmatch’s policy to inform users that the database could be used for other uses,” the company said in a statement after DeAngelo’s arrest.

The idea of cops poking around DNA databases hasn’t stopped platforms from trying to onboard new customers, however. Companies such as 23andMe heavily advertised during the holiday season, pitching a DNA test as the perfect gift for mom and dad. “100% family,” one ad said.

Indeed, for Family Tree DNA at least, working with the police is now a selling point.

Motherboard’s Jason Koebler wrote last year that genealogy databases may seem benign, but it’s becoming increasingly easy to foresee a future wherein our own genetic data is unexpectedly pitted against us—to violate our privacy; to wrongly incriminate us; to racially profile us. This is especially true because of the wide net that one person’s DNA test casts. A study published last year in Science predicted that 90 percent of Americans of European descent will be identifiable through genetic data volunteered by others within two or three years.

“The decision of one person to get tested implicates not only them but their relatives,” Vivian Chou, a predoctoral fellow at Harvard Medical School, told Motherboard in an email last December.

“I think that we as a society should be careful about any action where one person can make the decision to ‘out’ multiple people's data,” Chou added.

That Family Tree DNA is riding the forensic wave to sell its product is not surprising. (One popular true crime podcast that I listen to is now sponsored by 23andMe.)

What remains to be seen, however, is whether consumers will fight these dystopian outcomes. Even if you’ve already handed your DNA over to a startup, in some cases, it’s not too late to delete it.