Associated Press

Associated Press

SACRAMENTO, CALIF.

More than three decades after his trail went cold, one of California’s most prolific serial killers and rapists was caught by using online genealogical sites to find a DNA match, prosecutors said Thursday.

Investigators compared the DNA collected from a crime scene of the Golden State Killer to online genetic profiles and found a match: a relative of the man police have identified as Joseph James DeAngelo, 72, who was arrested at his suburban Sacramento home Tuesday.

Authorities didn’t give the name of the site, one of many that allows people to send in their DNA and find long-lost relatives, such as Ancestry and 23andMe.

They also didn’t outline the rest of the investigative process – how they used that match to home in on DeAngelo, the former police officer accused of being California’s notorious Golden State Killer. Despite an outpouring of thousands of tips over the years, DeAngelo’s name had not been on the radar of law enforcement before last week, Sacramento County District Attorney Anne Marie Schubert said.

Contacted Friday, Ancestry and 23andMe.com said they weren’t involved.

Meanwhile, central California police say the former police officer accused in a series of killings and rapes is also the prime suspect in the 1975 death of a community college teacher.

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