A US soldier pleaded guilty Wednesday to being an accessory to the rape and murder of a 14-year-old Iraqi girl and the slaying of her family in what was one of the most shocking atrocities in the Iraq war. Pfc. Bryan Howard, 20, also pleaded guilty to conspiracy to obstruct justice by lying to his superior officers about the March 12, 2006, attack in Mahmoudiya, 20 miles (32 kilometers) south of Baghdad. Howard could get up to 15 years in prison at a sentencing hearing expected to begin later Wednesday. Five soldiers were charged in the rape of Abeer Qassim al-Janabi and the killings of her, her parents and her younger sister. Two of the soldiers previously pleaded guilty and said Howard's role was minimal.