Mary Margaret Guilfoyle, a 24-year-old white female college student, was murdered on October 24, 1972, in Santa Cruz County, California. She was last seen hitchhiking to an interview when she was picked up by Herbert Mullin, a local man later identified as a serial killer. Mullin stabbed her to death during the drive, then partially dissected her body and scattered her remains in the Santa Cruz Mountains. Her skeletal remains were discovered on February 11, 1973, near Bonny Doon, California.
Initially, law enforcement suspected Edmund Kemper, another serial killer active in the area at the time, might have been responsible for Guilfoyle's murder. However, further investigation revealed that Herbert Mullin was the perpetrator. Mullin confessed to the killing, stating that he believed human sacrifices were necessary to prevent catastrophic earthquakes. He claimed that voices in his head instructed him to commit the murders.
Herbert Mullin was arrested on February 13, 1973, after committing a series of murders in the Santa Cruz area. He was convicted of two counts of first-degree murder and eight counts of second-degree murder, receiving a life sentence. Mullin died in prison on August 18, 2022, at the age of 75.
