Associated Press - November 21, 2009 7:14 PM ET

PLEASANTON, Calif. (AP) - The mysterious death in 1975 of Karen Rose Robinson is a mystery no more.

The Alameda County Sheriff's Department says the 21-year-old Oakland woman - whose body was found off a dark road in Pleasanton 34 years ago - died of a heroin overdose.

The case was classified as a homicide after Robinson's boyfriend told officers in 1975 he had dropped her off near Oakland City Hall on the night she died.

Now, the boyfriend says he was selling heroin at the time for the Black Panthers, and that Robinson overdosed after shooting too much of the drug without his knowledge.

He was worried about being blamed for the killing, so he moved Robinson's body to the road where she was eventually found.

Sgt. Scott Dudek, the cold case supervisor, says the man's story has helped bring closure and that the case is finally closed.

Information from: Contra Costa Times

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