SACRAMENTO, Calif. (AP) — More than three decades after his trail went cold, one of California’s most prolific and elusive serial killers was caught when investigators matched crime-scene DNA with genetic material stored by a relative on an online genealogical site, prosecutors said Thursday.

Authorities have said the DNA tied former police officer Joseph James DeAngelo, 72, to most of the 12 killings he is accused of committing between 1976 and 1986 as part of the Golden State Killer case.

Investigators also allege DeAngelo raped more than 50 women during that period.

Authorities declined to name the DNA site used to track the DNA.

Companies such as and 23andMe charge customers to use their DNA to produce genetic profiles that determine ethnicity and can identify long-lost relatives, among other services. Both companies said Thursday they weren’t involved in the case against DeAngelo.

Sacramento County District Attorney Anne Marie Schubert said investigators surreptitiously obtained his DNA last week from discarded material that ended up matching DNA at crime scenes.

Police received thousands of tips over the years, but DeAngelo’s name had not been on the radar of law enforcement before last week, Schubert said.

In other developments Thursday, police in Visalia said DeAngelo is a suspect in the 1975 killing of community college teacher Claude Snelling in the farming community about 40 miles (64 kilometers) south of Fresno.

If the link is confirmed, it would boost the number of victims to 13 in the serial killing case.

DeAngelo worked as a police officer in nearby Exeter from 1973 to 1976, and police in the region believe he also is the Visalia Ransacker, responsible for the death of Snelling, who was fatally shot while stopping someone from kidnapping his 16-year-old daughter, and about 100 burglaries.

Visalia police Chief Jason Salazar said Snelling’s death and the region’s burglaries weren’t part of the tally of crimes authorities released Wednesday in the serial killing case because investigators lacked DNA evidence on those crimes.

Salazar said fingerprints and shoe tracks will be eyed for matches to DeAngelo. Detectives are also looking to see if any items taken during the Visalia burglaries are uncovered during the investigation.

In addition, DeAngelo matches the description of Snelling’s killer, Salazar said, and the attacker used sophisticated pry tools to gain entrance to locked homes, just as authorities say DeAngelo did in other crimes.

The culprit also wore a ski mask and eluded capture because of an apparent deep-knowledge of police work.

“He always had a good escape route,” Salazar said.

Farrel Ward, 75, served on the Exeter Police Department with DeAngelo. Ward called him a “black sheep,” saying he was quiet and didn’t fit in with other officers.

Ward said it’s possible that DeAngelo helped with a search in a killing he’s now suspected of committing. Ward doesn’t recall DeAngelo directly working on the case but said it’s possible he joined the hunt for the killer.

Ward said he thought DeAngelo was overqualified for the small-town job because he graduated from Sacramento State with a degree in criminal justice.

“He knew everything about everything, but he didn’t have common sense about him,” Ward said

Investigators searched DeAngelo’s home on Thursday, looking for class rings, earrings, dishes and other items that were taken from crime scenes.

Authorities were also seeking weapons and other items that could link the suspect to the crimes, Sacramento County sheriff’s Lt. Paul Belli said. He declined to say what, if anything, investigators had found.

Retired FBI profiler Clint Van Zandt said he and others have speculated that the serial killer had police or military training because of the sophistication of the crimes and the suspect’s ability to elude capture.

DeAngelo had both. He served six years as a police officer after serving for nearly two years in the Navy during the Vietnam War. After leaving the Exeter police department, he joined the Auburn Police Department outside Sacramento. Auburn fired him in 1979 after he was caught shoplifting a hammer and dog repellent.

Investigators have linked DeAngelo to 11 killings that occurred after he was fired.

“There may have been a revenge aspect to it,” Van Zandt said of the crimes. “He was going to show police that he was smarter than any of them and that it was a mistake to fire him.”

Investigators said DeAngelo appeared to stop killing and raping after 1986 and settled down to steady employment and a middle-class life.

Profilers have said most serial killers usually don’t stop until they die or get arrested, but a few have voluntarily quit.

Scientists developed a way to identify rapists and others through DNA fingerprinting in 1986, the same year as the last attack by the Golden State Killer.

Experts noted that DeAngelo likely knew about the highly publicized DNA breakthrough.

“He knew police techniques,” said John Jay College of Criminal Justice professor Louis Schlesinger. “He was smart.”

James Huddle said he always hoped police would catch the killer whose attacks prompted him to buy a pistol.

But he was stunned to find out the man arrested was DeAngelo, his former brother-in-law.

Huddle said it was “still just going crazy in my mind.”