Police have named their prime suspect for the rape and murder of the ex-wife of Righteous Brothers singer Bill Medley more than four decades ago.
Los Angeles County Sheriff Jim McDonnell said investigators believe Kenneth Eugene Troyer was responsible for the January 1976 killing of Karen Klaas.
They used a controversial DNA to identify Troyer as their suspect, and said that he was killed by the police in 1982.
Ms Klaas, 32, was attacked as she returned to her home in Hermosa Beach, and was sexually assaulted and strangled. She never regained consciousness and died a few days later in hospital.
Investigators used a controversial DNA testing technique, known as familial DNA, to compare a sample of DNA that was collected at the crime scene and were able to identify a "first-degree relative" of Troyer, Sheriff's Captain Steve Katz said.
Officials would not identify the relative and would only say the sample they used was in a state database of convicted criminals.
The technique, which has raised ethical issues in the forensics community, allows investigators to search law enforcement databases to identify likely relatives of the person who may have committed the crime.
Law enforcement officials have argued the technique can provide investigators with valuable leads.
"Because of the familial DNA search, detectives were able to link Troyer's DNA and positively confirm his identity as the killer," Mr McDonnell said.
Standing alongside Medley and more than a dozen other law enforcement officials, he said: "Familial DNA search is the only reason Troyer was identified in this horrific crime."
Troyer, who had been suspected of committing several other sexual assaults in California, was shot and killed by police after escaping from a California prison in 1982, Mr McDonnell said.
As investigators began to focus on him as a possible suspect last year, they were able to obtain a sample of his DNA that was held in the Orange County coroner's office and conclusively link him to the murder of Ms Klaas, Mr Katz said.
The arrest brought closure to a family that has struggled with questions for decades, Medley said.
He said: "It's been something we've been hoping for and speculating about for 40 years and all of a sudden they say, 'We got him and here's who did it'.
"It's just nice to be able to close the book on this."