WASHINGTON — After the Central Intelligence Agency transferred Abu Zubaydah to the American military prison at Guantánamo Bay, Cuba, and he was brought before a panel of officers for a hearing in March 2007, he described in broken English how he had been tortured in the agency’s black-site prisons.

He said his body had shaken when he stood for hours, naked and shackled in a cold room and unable to shift his weight to an injured leg. He spoke of his humiliation at having to relieve himself in a bucket in front of other people, “like an animal.” And he described being waterboarded until he stopped breathing and required resuscitation.

Image Abu Zubaydah, who the C.I.A. mistakenly thought was a top official in Al Qaeda. Credit... U.S. Central Command, via Associated Press

“They shackle me completely, even my head; I can’t do anything,” Mr. Zubaydah said. “Like this, and they put one cloth in my mouth and they put water, water, water.” At the “last point before I die,” he said, interrogators stood the board back up and “make like this” — he made breathing noises — “again and again they make it with me, and I tell him, ‘If you want to kill me, kill me.’ ”