Sam Shockley and Miran Thompson had the type of criminal pasts that led to their imprisonment at the notorious and reputedly escape-proof Alcatraz Federal Prison in San Francisco Bay.
Thompson was serving life plus 99 years for kidnapping and murder. He had escaped from confinement eight times before being sent to Alcatraz. Shockley was serving a life sentence for robbery and kidnapping.
Those same pasts apparently led them to believe that they could do what had not been done before: escape from Alcatraz. That effort began on May 2, 1946, with a prison uprising intended, ultimately, to allow a group of inmates to commandeer the prison ferry.
The escape attempt began well, with the prisoners gaining access to weapons and keys. Their efforts were slowed by the lack of a key that would allow them to get to the ferry. The delay allowed guards to sound the alarm.
Unable to escape the island, the inmates instead engaged in futile violence. As the Battle of Alcatraz began, federal forces mobilized to retake control of the prison.
Sam Shockley, Miran Thompson, and Clarence Carnes survived the siege and were tried on federal charges for the killings of two guards. Carnes was sentenced to life imprisonment. Shockley and Thompson were sentenced to death.
They were executed in the gas chamber at San Quentin on December 3, 1948.
The Federal Death Penalty Project 