Alameda County Sheriff's investigators say they can now close the book on a 34-year-old cold case in Pleasanton.
The body of Karen Rose Robinson, 21, of Oakland, was discovered on a dark road in 1975.
Investigators originally classified the case as a homicide after Robinson's boyfriend told officers he had dropped her off near Oakland City Hall on the night she died, according to Sgt. Scott Dudek.
But investigators now believe that Robinson died of a heroin overdose. The boyfriend now says he was selling the drug at the time for the Black Panthers and that she injected too much of it without him knowing, Dudek said.
Dudek, who supervises the cold case unit, said the man told investigators he didn't want to be blamed for Robinson's death, so he moved her lifeless body to the dark road where she was discovered.