The US Army has opened an investigation into injuries suffered by a serviceman who was beaten up during A training exercise.
Guantanamo detainees wear a distinctive orange jumpsuit
Sean Baker says he received injuries from fellow soldiers while posing as a detainee at the Guantanamo Bay camp for al-Qaeda and Taleban suspects.
He blames officers for the botched exercise, and says he suffers seizures as a result.
The army had previously said Mr Baker's injuries occurred in the line of duty.
Mr Baker, 37, was a member of a military police unit based in Kentucky when it deployed to Guantanamo Bay in 2003.
In January of that year he volunteered to act as an unco-operative detainee for training purposes and put on an orange prison jumpsuit.
He argues that other participants were not made aware that he was a soldier.
During the exercise, Mr Baker says, military police choked him and slammed his head against the floor.
Mr Baker says he told them he was a US soldier but the beatings continued until the jumpsuit was yanked down, revealing his uniform.
Mr Baker - who has complained of traumatic brain injury - was subsequently honourably discharged.
The army initially said the discharge was unrelated to the exercise, but later acknowledged the injuries sustained at the time had been a factor.
Mr Baker told the Los Angeles Times: "What happened to me is something that should never have happened to any American soldier."
In a letter to the army, Congressman Ben Chandler of Kentucky urged the military to turn over Mr Baker's medical records and said his claims were "deeply troubling".