A U.S. soldier accused of massacring 16 Afghan civilians last year has pleaded guilty to murder and other charges, thereby avoiding execution. On Wednesday, Staff Sgt. Robert Bales formally admitted to killing nine children and seven adults during a nighttime attack on two Kandahar province villages in March 2012. Defense attorneys say Bales may have suffered a traumatic brain injury and post-traumatic stress disorder from four tours in Iraq and Afghanistan. Appearing before a military judge, Bales expressed regret for the massacre, saying: “There’s not a good reason in this world for why I did the horrible things I did.” His trial last year featured the video testimony of more than a dozen Afghan witnesses and victims. The witnesses, including several children, recalled being shot at and seeing their loved ones murdered. A hearing is set for August to determine if Bales will be sentenced to life in prison with or without the chance of parole.