Elizabeth Ann Duncan was born about 1904. She was described as a drifter, said to have married 20 times and at one time operating a brothel in San Francisco. She had one child, Frank, and made him the center of her life.  At times distressed about her life, Elizabeth Duncan tried to commit suicide. During her recovery, she was cared for by a nurse, Olga Kupzyck, who was 30. Frank, then 29 and a lawyer, secretly married Kupzyck. Elizabeth Duncan interfered with them and forced them to separate. By 1958 Olga was pregnant with their first child. In 1958, Olga Duncan disappeared; she was seven months pregnant with a child by her husband Frank. Her mother-in-law Elizabeth Duncan first drew suspicion when police discovered she had illegally obtained an annulment of the marriage of her son Frank Duncan and his wife Olga. Elizabeth Duncan and Ralph Winterstein, 25, whom she hired, secured the separation by posing in court as the young couple.

Nearly a month later, investigators found the young woman’s body in the Casitas Pass of Carpinteria, California in Ventura County. Augustine Baldonado, 25, confessed that he and Luis Moya, 22, had been offered $6,000 to kill her by Elizabeth Duncan, the victim’s mother-in-law. They directed the police to the site of the body. According to the coroner and their confession, the two men kidnapped the woman, sexually assaulted her, beat her with a pistol, strangled her, and buried her body in a shallow grave. She may still have been alive when buried. Elizabeth Duncan took the stand in her defense, admitting to talking to the two other suspects but saying they were blackmailing her. The jury took 4 hours and 51 minutes to find her guilty. She was sentenced to death in December 1958. After appeals, which upheld the lower court, she was executed by the gas chamber in 1962.