Updated

The highest-ranking soldier charged in the Abu Ghraib (search) scandal pleaded guilty Wednesday to five charges of abusing Iraqi detainees at the prison as a two-day court-martial opened at a U.S. base in Baghdad.

U.S. Army reservist Staff Sgt. Ivan "Chip" Frederick, 38, of Buckingham, Va., admitted to allegations of conspiracy, dereliction of duty, maltreatment of detainees, assault, and committing an indecent act. He was expected to be sentenced Thursday.

Under a plea bargain deal, several other charges against Frederick were dropped, according to his attorney, Gary Myers. Frederick — a military policeman and a corrections officer in civilian life — has agreed to cooperate fully in future investigations and courts martial, and will testify in future trials.

The Abu Ghraib prisoner scandal broke in April with the worldwide publication of photos and videos showing American soldiers abusing and humiliating naked Iraqi detainees.

Frederick is alleged to have watched as a group of detainees were made to masturbate while other soldiers photographed them. He also is accused of jumping on a pile of detainees, stomping on detainees' hands and bare feet, and punching one in the chest.

In addition, Frederick allegedly helped place wires in a detainees' hands and told him he would be electrocuted if he fell off a box.

Frederick is one of seven members of the Cresaptown, Md.-based 372nd Military Police Company charged in the scandal. One, Spc. Jeremy C. Sivits, of Hyndman, Pa., is serving a one-year prison sentence after pleading guilty in May to three counts.

Spc. Armin Cruz, 24, a Military Intelligence soldier, was sentenced last month to eight months of confinement, reduction in rank to private, and a bad conduct discharge for his part in the scandal.

Frederick, who was in charge of the night shift at the "hard site" facility at Abu Ghraib, told military judge Army Col. James Pohl that Military Intelligence and civilian interrogators "would tell us what conditions to set for (detainees)."

That included removing detainees' clothing, depriving them of sleep, or taking away their cigarettes, Frederick said. He said they wanted detainees "stressed out, wanted them to talk more."

During a notorious Nov. 4 incident captured on camera and transmitted around the world, Frederick said he had helped place wires on a detainee's hands and told him he would be electrocuted if he fell off a box.

"I took one and wrapped it around his finger. Sgt. (Javal) Davis put one on his hand. Spc. (Sabrina) Harman one on his toe," he said.

Frederick said he thought the interrogator wanted him to scare the prisoner to help out with the interrogation.

"Did you think what you were doing was right?" the judge asked.

"I was wrong about what I did and I shouldn't have done it. I knew it was wrong at the time because I knew it was a form of abuse," Frederick replied.

He said that photos taken of the incident were personal photos.

During another incident on Nov. 8, Frederick admitted that he joined another soldier who jumped on a pile of seven detainees accused of rioting. Frederick said the soldiers stomped on the prisoners' hands and feet, adding "I should have stopped it right there."

Detainees were strip-searched and remained naked, even after female soldiers arrived on the scene — which is against military rules. Frederick said he pulled out the ringleader in the group and hit him in the chest so hard that he needed medical attention.

"I stood him up and punched him in the chest. I was angry. They told me he was the ringleader. He hit a female soldier in the face with a rock," the soldier said.

During the same incident, Frederick said he watched as the group of detainees lined up naked against a wall with bags on their head, and then forced them to masturbate.

"I told one of them to masturbate. I grabbed his arm by the elbow, put it on his genitals and moved it back and forth with an arm motion and he did it," he said.

Then he and several other soldiers took pictures of the scene, he said.

Asked whether he believed the actions and pictures were "indecent," Frederick agreed but said he did it "just to humiliate" the Iraqi detainees.

The detainees were later piled into a naked, human pyramid. Twelve photos and a video were submitted as evidence.

Frederick blamed the U.S. military command for the problems, saying he had been given no training and no support.

"I had no support when I brought things up to my command. They told me to do what (Military Intelligence) told me to do," he said.

Frederick said he only learned afterward that there were regulations regarding treatment of the detainees.

The proceeding included witness testimony and other evidence but almost all the witnesses are participating by video teleconference from outside Iraq. Several of the defense witnesses are in Washington or Europe. One of the government's two witnesses also will testify remotely, from Mannheim, Germany.

The unusual arrangement ensured better cooperation from witnesses who were afraid to visit a war zone after a military appellate court refused to move the proceeding out of Iraq, according to Myers.