Harald Gullberg, a 66-year-old Swedish man, was found dead in Lincoln Park, San Francisco, on June 4, 1975. His death is believed to be connected to an unidentified serial killer called The Doodler, who operated in 1974 and 1975 and targeted gay men in bars and nightclubs, reportedly sketching victims before fatally stabbing them. Gullberg is described as the last known victim attributed to that attacker.

Investigators identified a strong suspect in January 1976 — described as a Black man between 19 and 25 — but no charges were filed. Multiple surviving victims gave descriptions, and the Doodler is suspected of killing between six and sixteen people, though the exact total is unknown. Renewed investigative efforts and an increased reward have been reported as authorities continue to seek leads.