Police Identify Killer of Slain Righteous Brothers Singer Bill Medley's Ex-Wife

It was a 41-year-old cold case that has finally came to an end.

The Los Angeles County Sheriff's Department has identified the man they say killed the former wife of Righteous Brothers singer Bill Medley.

Read: Dad of Murdered Jogger Appeals to Lawmakers to Adopt Divisive DNA-Match Technique to Find Her Killer

In a press conference attended by Medley and his son, Darrin on Monday, authorities said Kenneth Eugene Troyer, a serial rapist shot dead after escaping prison in 1982 was confirmed as Karen Klaas' killer.

Troyer was 29 at the time of the January 30, 1976 murder. Klaas was 32. 

District Attorney Jackie Lacey said familial DNA was used as a “last resort” and is an “invaluable resource” for cold cases.

Familial DNA has been used to track who killed the “Unchained Melody” singer’s first wife. The process matches the DNA of a suspect to other family members such as a father, son, or even a cousin.

Sheriff Jim McDonnell said Troyer’s DNA was found in 1999 and using familial DNA in 2011 yielded no match, however, in 2016, the match was discovered.

“You hold out hope. You want to close the book. You want to know what happened, why it happened,” Bill Medley said of the 41-year struggle of not knowing who killed his former wife.

He added: “It's just nice to close the book on this. When I was told, I became numb.”

“It's amazing because I did not believe we would ever identify who had committed this crime," Darrin, Klaas' son, added.

In 1976, a suspicious stranger was seen in the Hermosa Beach neighborhood of Los Angeles where Klaas lived.

Read: Murder of 'Righteous Brothers' Singer's Ex-Wife Is Solved 41 Years Later Through DNA

Her neighbors tried to warn her, but it was too late. When they came to the house on January 30, they discovered she had been viciously attacked and raped.

Two witnesses saw the killer fleeing the house and described the man as “shaggy-haired” and bearded.

Klaas was taken to a nearby hospital and remained in a coma for five days before eventually passing away.

It became a famous cold case in the area until recently, as police can now close the case.

Watch: Cops: Jogger 'Put Up a Ferocious Fight' Against Attacker Before Her Death