Several years ago, the Supreme Court considered the case of Alonzo Jay King Jr. Arrested in an assault in Maryland, he ended up being charged and convicted in an unsolved rape case after a sample of his DNA, which police collected while booking him, returned a match in a statewide database. King, who had been sentenced to life in prison, argued that the Maryland law allowing the warrantless, suspicionless collection of his DNA violated the Fourth Amendment.

The justices narrowly ruled against him, drawing a sharp dissent from Justice Antonin Scalia, who criticized invasive genetic searches of people who would still be legally innocent. “Perhaps the construction of such a genetic panopticon is wise,” he wrote, joined by justices Ruth Bader Ginsburg, Sonia Sotomayor, and Elena Kagan from the court’s left. “But I doubt that the proud men who wrote the charter of our liberties would have been so eager to open their mouths for royal inspection.”

Six years later, it turns out the American people may have built that genetic panopticon themselves, one self-swab at a time. California police used a commercial genealogy database to find the man they say is the Golden State Killer, a serial murderer and rapist who had eluded them for decades. Now, an imminent Supreme Court ruling could rewrite how law enforcement uses these DNA searches.

California law enforcement had long been stumped about the identity of the man who committed at least a dozen murders and more than 50 rapes in a spree of terror across the state in the 1970s and 1980s. That changed when investigators used a DNA sample from one of the crime scenes—“a never-touched DNA sample from a 37-year-old murder in Ventura County that was sitting in a freezer,” The New York Times reported—and submitted it to GEDmatch.



The popular, no-frills site is run by two men in Florida and does not perform its own tests. Instead, it allows users to upload and compare DNA profiles created by other services, such as Ancestry and 23andMe. This open-source system allowed investigators to avoid the need for a warrant, which genealogy services typically demand before handing over genetic information.