Prison guard Spc. Jeremy Sivits (search), who took photos of abuse at the Abu Ghraib (search) detention center in Iraq, described soldiers laughing and joking as they beat, stripped and sexually humiliated detainees, according to newspaper reports.

Sivits, the first soldier scheduled to be court-martialed in the abuse scandal, was expected to plead guilty Wednesday in Baghdad. He has cooperated with prosecutors and faces lesser charges than his colleagues.

Sivits' statements are the most in-depth descriptions of the abuse by a defendant to have been made public. Lawyers for the soldiers that Sivits named said his statements were "fabricated" and questionable because of his plea deal.

In one instance, a prisoner handcuffed to a bed with bullet wounds in his legs screamed "Mister, mister, please stop," as Military Police Cpl. Charles A. Graner (search) struck him with a police baton, according to statements Sivits made to military investigators.

"I was laughing at some of the stuff that they had them do," Sivits told investigators in January. "I was disgusted at some of the stuff as well."

Transcripts of Sivits' statements were provided to The Washington Post by Harvey Volzer, a lawyer representing Spec. Megan M. Ambuhl, another soldier charged in the case. The New York Times and the Los Angeles Times, which also cited investigative documents, did not name the source who provided them.

Ambuhl was the only soldier who Sivits did not accuse of wrongdoing in the statements.

Sivits said his superiors were unaware of the abuse, which came to light after another guard tipped authorities in January.

The other guards facing charges have said they acted on orders from superiors or from military intelligence, and all six have declared their innocence.

Guy Womack, an attorney for Graner, said Sivits' statement were of questionable value because he appeared to have agreed to a plea bargain with authorities.

Sivits described Graner as one of the ringleaders. The former Pennsylvania prison guard was always "joking, laughing, pissed off a little, acting like he was enjoying it," Sivits said.

He said Graner once punched a detainee in the head so hard the man fell unconscious.

Sgt. Ivan L. "Chip" Frederick II forced naked detainees to masturbate, showing them how to do it "right", and seemed to enjoy watching the prisoners beaten, Sivits said.

Sivits said Sgt. Javal Davis threw himself on a pile of prisoners and "then stomped on either the fingers or toes of the detainees," as they screamed in pain.

Paul Bergrin, a Newark lawyer who is representing Davis, said Sivits's statement was "fabricated" and "self-serving."

"This is in order to cover up for his own misdeeds and mischievous behavior," he told the Post.

Womack said he doubted Graner would have hit a detainee.

"I don't think he was that kind of guy," Womack told the New York Times. "He would have done it if he was ordered to do it."

Womack said that military intelligence soldiers were in one of the graphic photographs, indicating that they were aware of what was going on.

Bill Lawson, Frederick's uncle, told the Post that Frederick "shoved" one prisoner who was trying to "start some kind of a scuffle." Frederick has maintained that "he has never lifted a finger against any prisoner in Iraq," Lawson said.

Sivits said Spc. Sabrina Harman and Pfc. Lynndie England, who is pregnant with Graner's child, smiled in some of the pictures, but that Harman sometimes "had a look of disgust on her face."

Harman wrote the word "rapist" on the leg of one inmate after she learned he had raped someone, he said.

Sivits said he was told not to report the abuse.

"I was asked not to," he said. "And I try to be friends with everyone. I see now where trying to be friends with everyone can cost you."