On February 6, 1981, 28-year-old Manuela Witthuhn was found dead in her Irvine home after failing to arrive at work. Her parents discovered her in a sleeping bag; she had been raped and bludgeoned to death, with skull fractures listed as the cause. Ligature marks on her wrists and ankle indicated she had been bound. The attacker had pried open a sliding glass door to gain entry.

Manuela lived with her husband, David Witthuhn, who was in the hospital recovering from a viral infection at the time of the killing. Because the killer often targeted couples, his hospitalization likely spared his life. David became the primary suspect in the investigation and lived under suspicion for years; that scrutiny affected his jobs, housing and relationships and subjected him and a later wife to threatening phone calls.

The murder remained part of a wider series of violent crimes in California for decades, and the investigation continued to seek answers about who entered that Irvine home that February morning. If anyone knew Manuela, her routines, or saw unusual activity near her home around February 6, 1981, please share what can help the case.