A 73-year-old man in a nursing home was ordered to provide a DNA sample.
His daughter said authorities never notified her before swabbing her father for DNA in his bed a rehabilitation center, but once they told her afterward she understood and worked with them to eliminate people who conceivably could be the killer.
Investigators also revealed Thursday that DeAngelo is the prime suspect in the 1975 killing of a community college teacher, raising the total number of his alleged victims to 13.
They also didn't outline the rest of the investigative process - how they used that match to hone in on DeAngelo, the former police officer accused of being California's notorious Golden State Killer.
DeAngelo's public defender Diane Howard spoke for her client outside court.
He has been charged with eight counts of murder, and additional charges are expected, authorities said.
Ironically, DeAngelo continued to live in and around the areas where he allegedly conducted a reign of terror that had residents in the affected counties buying handguns for self-defense, acquiring dogs as early warning systems and putting multiple locks on their houses.
Investigators caught him by comparing DNA from crime scenes to profiles available on genealogical websites. They relied on a different website than they had in the OR search, and they did not seek a warrant for DeAngelo's DNA.
A Lake Worth, Florida-based company called GEDMatch acknowledged on Friday that its database "was used to help identify the Golden State Killer. although we were not approached by law enforcement or anyone else about this case or about the DNA".
Investigators started with DNA samples from crime scenes that were in storage to build a genetic profile of the suspected attacker, which they then uploaded into an online genealogy database to see if they could find a match. But Rogers said the company does not "hand out data".
Holes said officials did not need a court order to access GEDMatch's large database of genetic blueprints.
Police did not know when the results of the DNA tests will be in but said they are actively working the case.
Civil libertarians said the practice raises troubling legal and privacy concerns for the millions of people who submit their DNA to such sites to discover their heritage. Unfettered law enforcement access to our own and our relative's DNA information has the potential for abuse, however. The suspect, they said, was tied to many of those crimes through DNA. He declined to say what, if anything, investigators had found. "If an ordinary person can do this, why can't a cop?" He entered the information among 189,000 profiles at the genealogy website, YSearch.org, and the results led to a relative of the OR man.
Contacted Friday, both Ancestry and 23andMe.com said they weren't involved in the case. They created a family tree and used public records to identify the OR man. However, given the amount of documents linked to the case, a plea may not come for months.
At first, the Federal Bureau of Investigation and California investigators used his DNA to create a profile.
DeAngelo, a former police officer, probably would have known about the new method, experts said.
Inside the timeline of crimes by the "Golden State Killer".
The sample provided "overwhelming evidence that it was him", Ms. Schubert said.
"Obviously, you didn't want the East Area Rapist on the team", Phillips said.