No one went to the police.
Through a friend, Ma Duncan found two men, Luis Moya and Augustine Baldonado, and they reached a price: $3,000 for the job.
She pawned some jewelry for $175, stole $200 from her son's wallet, kept a few bucks for herself and gave them a down payment of $335.
On Nov. 18, 1958, Moya and Baldonado borrowed a car and a gun and lured Olga from her apartment on the pretext that her husband was drunk in the back seat of their car. She was still in her bathrobe and slippers when they shoved her inside the car. She fought back, kicking and scratching. The men panicked and pistol-whipped her so hard that they broke the borrowed gun.
They beat her again, choked her and dumped her body in a shallow grave they dug in a culvert at the Casitas Dam construction site near Ojai. No one knows whether she was dead or alive when they buried her.
Weeks later, both men were arrested on unrelated charges. Ma Duncan, fearing the men would spill their murderous secret, told her son that they had been blackmailing her about the annulment she tried to stage. Her son went to police, intending to get the men in more legal trouble.
But it didn't work out that way. Police soon became suspicious about Olga's disappearance and pressed the men, who confessed and implicated Ma Duncan. They would later say that if they had known Olga was pregnant, they would not have killed her.
Ventura County was horrified--a mother-in-law accused of killing her son's wife and her own unborn grandchild. The courtroom was crowded from Day One.
Frank Duncan defended his mother, joined by Los Angeles attorney S. Ward Sullivan. Five years earlier, Sullivan had lost the case defending Jack Santo and Emmett Perkins, the accomplices of good-time girl Barbara Graham. Along with Graham, they were sentenced to death.
At the attorneys' table and on the witness stand, Frank was not the picture of a grief-stricken husband. Although he testified that his relationship with his wife was one of "love and affection," he also admitted that he had never so much as talked to her in the 10 days before her disappearance.
When asked if his mother tried to break up his marriage, he replied, "Let's just say she hindered its development."
Despite the prosecution's 44 witnesses, including the hit men, Ma Duncan steadfastly denied any knowledge of the crime. Four weeks after the trial began, Ma Duncan was convicted of first-degree murder and sentenced to be executed.
Moya and Baldonado, who had already confessed and been sentenced to death, tried to flee by sawing through their cell bars with smuggled hacksaw blades. They beat two guards and held them hostage until tear gas quelled their escape attempt.
After three years of appeals, Ma Duncan walked into the gas chamber with poise and dignity--head held high, her face betraying no emotion--but without her trademark horn-rimmed glasses. Unlike Graham, Duncan did not ask for a blindfold. But earlier, when she had asked to be sedated, officials had refused.
Before the gas enveloped her, she said, "Where's Frank? I am innocent." Frank wasn't there; he was working on getting his mother's execution delayed. It was Aug. 8, 1962.
Like Graham, Duncan was a woman executed with two accomplices. She died first, and alone. Three hours later, her accomplices laughed and talked as they strolled into the gas chamber, where they took their seats, side by side.
"It's down!" yelled Baldonado of the cyanide pellets; he was loud enough to be heard through the glass partition.
"I can smell it. It doesn't smell good," Baldonado added.
While his mother was in prison, Frank Duncan remarried, this time to an attorney (whom he divorced some years later).
After his mother's execution, he moved to Los Angeles, where he practiced law and never again made headlines.
Twelve women are now on death row in California.