Bill Medley
Bobby Hatfield (L) and Bill Medley (R), The Righteous Brothers, were inducted into the Rock and Roll Hall Of Fame at the 18th Annual Rock and Roll Hall Of Fame in 2013. Getty

The murder of the ex-wife of Righteous Brothers singer Bill Medley has been solved after more than 40 years, thanks to a controversial DNA technique.

Karen Klaas, 32, was raped, strangled and left unconscious at her Hermosa Beach home on 30 January 1976, after dropping off her youngest child to school.

On Friday, the Los Angeles County Sheriff's Department said they solved her murder "through the use of familial DNA, which identified the killer", but no further details were given.

Familial DNA is a controversial technique that searches databases for a partial match by finding a relative of a suspect.

Los Angeles county sheriff Jim McDonnell and District Attorney Jackie Lacey are expected to provide additional information at a news conference on Monday, (30 January) which will also mark the 41st anniversary of her death.

Medley was by her hospital bedside while she remained in a coma, but she never regained consciousness and died on 4 February, 1976.

Although Medley was divorced from Klaas they had a 10-year-old son, Darrin, together. He once said: "She just was a very alive beautiful wonderful girl. One of the sweetest and even though we were divorced, it was a very friendly wonderful split."

However, he later told the Orange County Register in 2000 how he and his family wanted closure.

He said: "Karen was very loved and respected, and it was a horror what happened to her. She has a lot of friends who would like to see this resolved."

At the time of the attack, two witnesses reportedly saw a bearded man in a trench coat and blue jeans leaving her house, but he was never seen again.

Police traced a DNA profile of the killer in 2009, but it didn't match anyone on the national DNA database.

Medley later married Paula Vasu in 1986 where they now live in California. His classic song You've Lost That Lovin' Feelin' was named the most played record in the history of radio.

Co-written and produced in 1964 by Phil Spector, it is estimated to have been broadcast eight million times beating The Beatles' Yesterday and Otis Redding's Sittin' On The Dock of the Bay.