On August 21, 1971, there was a prisoner uprising in a housing unit at San Quentin, led by George Jackson. According to the state of California, lawyer-activist Stephen Bingham had smuggled a pistol concealed in a tape recorder to Jackson, who was housed in San Quentin’s Adjustment Center time awaiting trial for the murder of a prison guard. On August 21, 1971, Jackson used the pistol, an Astra 9-mm semi-automatic, to take over his tier in the Adjustment Center. In his failed escape attempt, six people were killed, including three prison guards, two white prisoners, and Jackson himself.

At the end of the roughly 30 minute rebellion, guards had killed George Jackson, and two other prisoners and three guards were dead. Of the remaining prisoners in the unit, six of them were put on trial for murder and conspiracy. They were known as the San Quentin Six. Three of them were acquitted of all charges, and three were found guilty of various charges. Hugo Pinell was convicted of assault on a guard. Although only convicted of assault, and another of the San Quentin Six had a murder conviction, by 1998, all of the men except Pinell had been set free.