Mary Ann Sarris was a 19-year-old waitress from Isla Vista who disappeared on December 6, 1976, while hitchhiking in the Isla Vista area. Her decomposed body was found by hikers in Drum Canyon in May 1977. The autopsy showed a small-caliber pistol shot to the head, a cause of death consistent with two other young women—Jacqueline Rook and Patricia Laney—whose cases were linked as the so-called look-alike murders because the victims shared long, straight hair, similar builds, and a pattern of hitchhiking.

Investigators identified Thor Nis Christiansen, a former service station employee from Goleta, as the primary suspect after a surviving victim, Linda Preston, recognized him in a Hollywood bar. Preston had escaped after Christiansen shot her in the ear while she was hitchhiking. Christiansen was arrested in July 1979, charged in the killings of Sarris, Rook, and Laney, and later pleaded guilty and received life sentences. The killings prompted local campaigns to discourage hitchhiking and to improve safety measures for women.