Elizabeth Ann Duncan

Elizabeth Ann Duncan (born Hazel Lucille Sinclaira Nigh (1904 in Kansas City, Missouri – August 8, 1962) was an American murderess. She was convicted of orchestrating the murder of her daughter-in-law in 1958. She was the last woman to be executed in California before the United States Supreme Court suspended the death penalty under Furman v. Georgia.

Duncan was convicted of hiring 24-year-old Augustine Baldonado and 23-year-old Luis Moya to murder her daughter-in-law, Olga Duncan, who was seven months pregnant at the time. All three were executed in the gas chamber at San Quentin State Prison on August 8, 1962, the last triple execution in California.

The trial began on February 24, 1959. Duncan testified that Moya and Baldonado attempted to blackmail her, refuting the accounts of every witness called by the prosecution, including Moya and Baldonado. Her attorneys then presented the theory that Olga was the victim of a ransom plot. The jury took 4 hours and 51 minutes to find her guilty on March 16, 1959; she was sentenced to death four days later. Frank, Burt M. Henson, and two other attorneys represented her in the appeals process; Henson was appointed by trial judge Charles Blackstock to represent Baldonado and Moya. Governor Pat Brown, an opponent of capital punishment, ultimately allowed the executions to proceed. Right up until the minutes before her execution, Duncan fought to save his mother's life.

When her son Frank threatened to move out of the apartment they shared, Elizabeth attempted suicide via an overdose of pills. During her recovery at Cottage Hospital in Santa Barbara, she was cared for by nurse Olga Kupczyk. Frank dated Kupczyk, then married her on June 20, 1958 after learning that she was pregnant. A furious Elizabeth harassed Olga at work, forcing her to change addresses several times, and even admitted in court to plotting to kidnap Frank "to try to talk some sense into him. I didn't want to lose Frankie. I couldn't stand life alone and I knew it." The couple separated two weeks after they married.

In November 1958, Olga Duncan disappeared. Her mother-in-law first drew suspicion when police discovered she had illegally obtained an annulment by hiring a man, Ralph Winterstein, to pose as Frank while she posed as Olga.