US military investigators tried in vain to get a former Guantanamo Bay prison commander reprimanded over the abuse of detainees, a report says.
There have been calls for the camp to close
Maj Gen Geoffrey Miller would have become the highest ranking officer to be punished over prison abuse.
But the Southern Command which runs the base said he committed no violations.
The report, released at a Senate committee hearing into the treatment of detainees, also mentioned multiple instances of abuse at the prison.
However, it added that only three instances were found which violated army policy, and there were no cases of torture or inhumane treatment.
Despite this, the report found that:
- Female interrogators touched detainees inappropriately and smeared them with a substance they described as menstrual blood, but which was fake blood
- Interrogators threatened to go after a detainee's family
- Military staff impersonated FBI and state department interrogators
- Duct tape was used to bind the head and mouth of a detainee chanting verses of the Koran
- A detainee was chained to the floor in the foetal position
- Cold, heat, loud music and sleep deprivation were used on detainees.
The report admonished Maj Gen Miller for failing to oversee the interrogation of a high-value detainee.
But Southern Command head Gen Bantz Craddock said the former commander had done nothing wrong, and forwarded the case to the army inspector general.
Maj Gen Miller, who took over at the prison in 2002, has been criticised by human rights groups for his methods.
He has since been involved with overseeing prisoners in Iraq and is currently in a position at the Pentagon unrelated to detainees.
Cases of abuse at the camp have prompted criticism from human rights groups and senior US politicians, some of whom have called for it to be closed.
US military officials say disciplinary or administrative action has been taken in all 10 cases of misconduct documented since prisoners were first brought to Guantanamo in January 2002.
Michigan Senator Carl Levin, the top Democrat on the Senate Armed Services Committee, said the report showed there were more than a few isolated cases of abuse.
"It is clear from the report that detainee mistreatment was not simply the product of a few rogue military police in a night shift," he said.