Initially, police thought Cosner left voluntarily, but his family didn’t believe this. Cosner had recently made $35,000 from a business deal and owned property, making a sudden disappearance unlikely.

Authorities later linked Cosner to serial killers Charles Ng and Leonard Lake. Ng and Lake, who met through a survivalist magazine, ran a horrific compound where they held people as sex slaves and murdered them. They were eventually caught shoplifting; Lake committed suicide by swallowing poison. At their compound, police found the remains of many victims, including Cosner’s belongings. Lake’s diary even mentioned Cosner.

Ng was convicted of 11 murders in 1999 after a long trial. Though he blamed Lake, a judge officially ruled Cosner a victim in 2001. Cosner’s body has never been found, but the evidence strongly suggests he was murdered by Ng and Lake. These two men are also suspected in the disappearance of several other people from San Francisco.