Beginning in late 1965, the application of torture against U.S. prisoners became severe. During the first six years in which U.S. prisoners were held in North Vietnam, many experienced long periods of solitary confinement, with senior leaders and particularly recalcitrant POWs being isolated to prevent communication. Robinson Risner and James Stockdale, two senior officers who were the de facto leaders of the POWs, were held in solitary for three and four years, respectively. The Alcatraz Gang was a group of eleven POWs who were held separately because of their particular resistance to their captors.
