According to documents made available recently and reviewed by the Associated Press, Manadil al-Jamadi was one of the CIA's "ghost" detainees at Abu Ghraib - prisoners being held secretly by the agency.
Al-Jamadi's death became known last year when the Abu Ghraib prison scandal broke.
US prison guards were seen in photos giving thumbs-up over his bruised and puffy-faced corpse which had been packed in ice.
The US military had previously said the death had been ruled a murder, but the exact circumstances under which he died were not disclosed at the time.
But documents now show al-Jamadi died in a position known as "Palestinian hanging". It is unclear whether that position was approved by the Bush administration for use in CIA investigations.
Several US military personnel are
on trial for torture at Abu Ghraib
Al-Jamadi died in a prison shower room during about a half-hour of questioning, before interrogators could extract any information, according to the documents, which consist of statements from US army prison guards to investigators with the military and the CIA's inspector-general's office.
One guard, Sergeant Jeffery Frost, said the prisoner's arms were stretched behind him in a way he had never before seen.
Frost and other guards had been summoned to reposition al-Jamadi, who an interrogator said was not cooperating. As the guards released the shackles and lowered al-Jamadi, blood gushed from his mouth "as if a faucet had been turned on", according to the interview summary.
The military pathologist who ruled the case a murder found several broken ribs and concluded al-Jamadi died from pressure to the chest and difficulty in breathing.
Dr Vincent Iacopino, director of research for Physicians for Human Rights, called the hyper-extension of the arms behind the back "clear and simple torture".
The European Court of Human Rights found Turkey guilty of torture in 1996 in a case of Palestinian hanging – a technique Iacopino said is used worldwide but named for its alleged use by Israel in Palestine.
US Navy SEALs had apprehended al-Jamadi as a suspect in the October 2003 bombing of Red Cross offices in Baghdad.
According to court documents, the SEALs punched, kicked and struck al-Jamadi with their rifles before handing him over to the CIA early on 4 November. By 7am that day, he was dead.