The mistake is in releasing them.
Released Detainees Rejoining The Fight
http://www.washingtonpost.com/wp-dyn/articles/A52670-2004Oct21.html
At least 10 detainees released from the Guantanamo Bay prison after U.S. officials concluded they posed little threat have been recaptured or killed fighting U.S. or coalition forces in Pakistan and Afghanistan, according to Pentagon officials.
One of the repatriated prisoners is still at large after taking leadership of a militant faction in Pakistan and aligning himself with al Qaeda, Pakistani officials said. In telephone calls to Pakistani reporters, he has bragged that he tricked his U.S. interrogators into believing he was someone else.
Well, now that is a serious problem.