Mark Dreibelbis was 15 when he was murdered on February 10, 1973, while camping in Henry Cowell Redwoods State Park near Felton, California. He was one of four teenage boys—Mark, Robert Michael Spector, David Allan Oliker, and Brian Scott Card—who encountered Herbert Mullin in the park. Mullin, posing as a park ranger, ordered the boys to leave and, after they refused, returned the next day and shot them. The four bodies were found on February 17, 1973.

Herbert Mullin was arrested soon after and later confessed to multiple killings committed between October 1972 and February 1973. His delusions, described in reports as driven by a belief that murders would prevent earthquakes, and a diagnosis of paranoid schizophrenia were central issues in the subsequent trials. Mullin was convicted on multiple counts and sentenced to life imprisonment.