One of the military police officers charged in the abuse scandal at Iraq’s Abu Ghraib prison has offered to plead guilty and has provided military investigators with a detailed account of how guards humiliated and beat detainees, in one case hitting a prisoner so hard he became unconscious.

Spec. Jeremy Sivits, one of the seven members of the 372nd Military Police Company facing charges in the case, told investigators in a sworn statement that other prison guards forced detainees to strip, masturbate and pile on top of one another. Staff Sgt. Ivan “Chip” Frederick forced two detainees to punch each other, Sivits told investigators, according to a transcript.

In another instance, he said, Spec. Charles Graner put a sandbag over a detainee’s head and “punched the detainee with a closed fist so hard in the temple that the detainee was knocked unconscious.”

“I walked over to see if the detainee was still alive,” Sivits said, according to the transcript. He lay there motionless with his eyes closed for about two minutes, Sivits said, before he moved “for the first time, like he was coming to.”

Transcripts of two statements Sivits made in January were provided by Harvey Volzer, a lawyer representing Spec. Megan Ambuhl, another soldier charged in the case. Sivits’ father has said that the family could not afford a civilian lawyer, and the identity of Sivits’ military attorney could not be learned Thursday night.

Sivits, 24, of Hyndman, Pa., admitted in the statement that he photographed the abuse but never reported it. His offer to plead guilty in the case has been accepted by the staff judge advocate overseeing his court-martial, according to a memo reviewed by The Washington Post and lawyers representing some of the other charged soldiers. It could not be determined which charge he has pleaded guilty to.

Sivits has been ordered to face a special court-martial, a proceeding similar to a misdemeanor trial in which defendants face a maximum prison sentence of one year. That, combined with the plea, indicates that he has agreed to testify against other soldiers in the case, Volzer and legal experts have said.

In his statement, Sivits implicated five of six other soldiers charged in the case. Lawyers representing the soldiers or their families have denied anything illegal was done.

Most of Sivits’ statement concerns the night of last Oct. 3. Frederick had asked him to come to holding cells in the Abu Ghraib prison where some new detainees had just arrived.

Sivits said that after he and Frederick got there, some detainees were put in a pile on the floor. Sivits said Sgt. Javal Davis ran into the room and “lunged into the air and landed in the middle of where the detainees were.”

Davis, 26, then stomped “on either the fingers or toes of the detainees,” he said, causing them to “scream loudly.” Sivits said Frederick hit a detainee in the chest “for no reason.”