golden state killer arrested

Announcing his arrest on Wednesday, authorities said Mr DeAngelo's name had never surfaced as a suspect prior to last week, when a DNA match was made.

Officials initially did not disclose how their investigation led to Mr DeAngelo, whose DNA had never previously been collected.

But yesterday, Steve Grippi, chief deputy district attorney for Sacramento County, said detectives narrowed their search by using genetic information available through commercial genealogy websites furnishing personal family histories to consumers who send DNA samples in for analysis.

Confirming details first reported by the Sacramento Bee newspaper, Mr Grippi said investigators compared DNA samples left by the perpetrator at a crime scene to genetic profiles on the ancestry sites, looking for similarities.

He did not address whether the websites volunteered the information or were subject to a search warrant or subpoena.

Detectives followed the family trees of close matches, seeking blood relatives who fit a rough profile of the killer.

The process produced a lead a week ago, pointing to Mr DeAngelo based on his age and whereabouts at the time of the attacks, Mr Grippi said.

Investigators found Mr DeAngelo, placed him under surveillance and obtained his DNA from a discarded object, finding a match to a crime scene sample. A second, more decisive sample was collected from him days later and came back positive on Monday.

Authorities have not disclosed the relative whose DNA helped solve the case.

Mr DeAngelo is known to have at least two adult children.