this is camp bucca, an american prison. during the iraq war, the most dangerous jihadis were locked up here, up to 20,000 of the country's angriest men. some americans who worked at camp bucca called it simply camp hell. it wasn't just crowded, it was violent. in 2005, riots broke out. detainees went on a rampage, taking over whole sections of the prison camp. american forces massed outside the fences, firing into the crowds. at least four prisoners were killed. >> now, this is camp bucca. >> reporter: major general doug stone was brought in to fix camp bucca. even he was wary of the inmates. here he is giving cnn's nic robertson a tour in 2008. >> we have about 2,000 identified al qaeda here in the theater internment facility. they're very hard to break. >> you have shields up here to protect us. everyone down here is crowded around, looking at us now. >> right. but this is not a place that you want to hang around. we don't want to stand here that