Elizabeth Duncan, known to friends and family as Ma, was executed in California's gas chamber on August 8, 1962. She was convicted of hiring two men to kill her pregnant daughter-in-law, so that Duncan could maintain her incestuous relationship with her son Frank. Although he was married, Frank lived with his mother. Afraid of being alone, Duncan sought to eliminate her son's wife, Olga Kupczyk Duncan, who she saw as a threat to the love between her and Frank.
After two delays and much effort from Frank, a lawyer, to save his dear mother, Duncan was executed. She is the last woman to have been executed by gas chamber in California.