Fort Bragg, N.C. ? Seeking to discredit claims that Pfc. Lynndie England was following orders, prosecutors portrayed her on Tuesday as an out-of-control soldier who was photographed mocking Iraqi prisoners “just for fun.”

On the first day of a hearing to determine whether England should be court-martialed for her actions at the prison, witnesses testified that the naked detainees shown with her in human pyramids and tethered to a leash were common criminals of little or no value to interrogators, abused only for sport.

An Army investigator, Paul Arthur, testified that when he interviewed England about the photos three months before they became public, she told him they were taken while “they were joking around, having some fun, during the night shift.”

Arthur said he believed the reservists from the 372nd Military Police Company, based on Cresaptown, Md., were responding to the stress of being in a war zone. Just before the pictures were taken in October 2003, there had been a prison riot at Abu Ghraib and some soldiers had been injured.

“It was just for fun, kind of venting their frustration,” Arthur testified.

But when asked whether that assessment applied to England, Arthur replied: “She never mentioned that she was frustrated. She said it was more for fun.”

Defense lawyers have said that the 21-year-old Army reservist from Fort Ashby, W.Va., was following orders from higher-ups and that the U.S. government has made her a scapegoat for an incident that stirred outrage in the Arab world.

Tuesday’s hearing was a preliminary step toward a general court-martial. England could face a maximum of 38 years in a military prison if convicted.

A second Army investigator, Warren Worth, testified that England never indicated she was an unwilling participant in the photos, and that she even took some of the pictures herself. He added that her job was in another part of the prison complex, and she had been warned that she didn’t belong in the area where the pictures were taken.

England is one of seven reservists from the 372nd who have been charged in the scandal. One, Spc. Jeremy C. Sivits, has already pleaded guilty and been sentenced to a year in prison.

Spc. Charles A. Graner Jr., 35, another soldier in England’s unit, also has been charged with abuses and was involved in a romantic relationship with England; he faces adultery charges for allegedly having sex with England last October. England is pregnant with Graner’s child.