A military jury has convicted a U.S. soldier of beating and humiliating Iraqi detainees at Baghdad's Abu Ghraib prison.

The military court in Fort Hood, Texas, found Specialist Charles Graner guilty Friday of beating prisoners, (forcing them to masturbate) and piling them naked atop each other.

Graner faces a maximum of 15 years in prison. He was one of the key figures seen in photographs of guards abusing prisoners.

Prosecutors argued that the soldier beat and humiliated the Iraqi detainees for fun. Graner's lawyer said intelligence agents ordered him to use physical violence to soften prisoners up for interrogation (break down their resistance to questioning).

The 36-year-old soldier is expected to testify for the first time in the trial later today (Saturday), before his sentence is pronounced.

In another military trial (Friday), a U.S. military court in Baghdad found a soldier guilty of murder for shooting a severely wounded Iraqi teenager last year. The defense said it was a mercy killing. The soldier was sentenced to a year in prison and discharged from the Army.