Although, there are reports suggesting that he might have spent only 10 months at this camp in 2004. If so then he had to be kept at some other undisclosed locations till his release from US custody in 2009.
Former inmates of Camp Bucca said this US military center was an “Al Qaeda school."
An al Jazeera article based on interviews with inmates of Camp Bucca offers this testimony on the conditions under which the current leader of ISIS was held there:
Extremists held in a US-run detention centre in Iraq were allowed to teach fellow detainees how to use explosives and become suicide bombers, a former inmate has told Al Jazeera. Adel Jasim Mohammed, a former detainee of Camp Bucca near Umm Qasr, said that US officials did nothing to stop radicals from indoctrinating young detainees at the camp. "Extremists had freedom to educate the young detainees. I saw them giving courses using classroom boards on how to use explosives, weapons and how to become suicide bombers," Mohammed said. "For the Americans we felt it was normal. They did not stop them [the radicals]." ... "In 2005, an extremist was sent to our camp. At first, Sunnis and Shias rejected his teachings. But we were told that he was imposed by the prison authority," he said. "He stayed for a week and recruited 25 of the 34 detainees - they became extremists like him."