But the next morning, he said, doctors and dentists arrived to care for their injuries. Beds and pillows were brought back in. They were fed. Everyone was nice, Mr. Abd said. Then at night, the same crew with "Joiner" would return and strip them and handcuff them to the walls.

Much of the evidence of abuse at the prison came from medical documents. Records and statements show doctors and medics reporting to the area of the prison where the abuse occurred several times to stitch wounds, tend to collapsed prisoners or see patients with bruised or reddened genitals.

Two doctors recognized that a detainee's shoulder was hurt because he had his arms handcuffed over his head for what they said was "a long period." They gave him an injection of painkiller, and sent him to an outside hospital for what appeared to be a dislocated shoulder, but did not report any suspicions of abuse. One medic, Staff Sgt. Reuben Layton, told investigators that he had found the detainee handcuffed in the same position on three occasions, despite instructing Specialist Graner to free the man.

"I feel I did the right thing when I told Graner to get the detainee uncuffed from the bed," Sergeant Layton told investigators.

Sergeant Layton also said he saw Specialist Graner hitting a metal baton against the leg wounds of a detainee who had been shot. He did not report that incident.

Sgt. Neil Wallin, another medic, recorded on Nov. 14: "Patient has blood down front of clothes and sandbag over head," noting three wounds requiring 13 stitches, above his eye, on his nose and on his chin.

Sergeant Wallin later told investigators that when he got to the prison: "I observed blood on the wall near a metal weld, which I believed to be the place where the detainee received his injury. I do not know how he was injured or if it was done by himself or another."

He also told investigators that he had seen male detainees forced to wear women's underwear and that he had seen a video in which a prisoner known to smear himself with his own feces repeatedly banged his head against the wall, "very hard."

Helga Margot Aldape-Moreno, a nurse, told investigators that in September she reported to the cell to tend to a prisoner having a panic attack, and that, opening the door, she saw naked Iraqis in a human pyramid, with sandbags over their heads. Military police officers were yelling at the detainees, she said.

Ms. Aldape-Moreno tended to the prisoner, she said, then left the room and did not report what she saw until the investigation began in January.