Today, Mr. Qumu, 51, is a notable figure in the Libyan rebels’ fight to oust Col. Muammar el-Qaddafi, reportedly a leader of a ragtag band of fighters known as the Darnah Brigade for his birthplace, this shabby port town of 100,000 people in northeast Libya. The former enemy and prisoner of the United States is now an ally of sorts, a remarkable turnabout resulting from shifting American policies rather than any obvious change in Mr. Qumu.  He was a tank driver in the Libyan Army in the 1980s, when the Central Intelligence Agency was spending billions to support religious militants trying to drive Soviet troops out of Afghanistan. Mr. Qumu moved to Afghanistan in the early 1990s, just as Osama bin Laden and other former mujahedeen were violently turning against their former benefactor, the United States.  He was captured in Pakistan after the Sept. 11, 2001, terrorist attacks, accused of being a member of the militant Libyan Islamic Fighting Group, and sent to Guantánamo — in part because of information provided by Colonel Qaddafi’s government.  “The Libyan Government considers detainee a ‘dangerous man with no qualms about committing terrorist acts,’ ” says the classified 2005 assessment, evidently quoting Libyan intelligence findings, which was obtained by The New York Times. “ ‘He was known as one of the extremist commanders of the Afghan Arabs,’ ” the Libyan information continues, referring to Arab fighters who remained in Afghanistan after the anti-Soviet jihad.  When that Guantánamo assessment was written, the United States was working closely with Colonel Qaddafi’s intelligence service against terrorism. Now, the United States is a leader of the international coalition trying to oust Colonel Qaddafi — and is backing with air power the rebels, including Mr. Qumu.  The classified Guantánamo assessment of Mr. Qumu claims that he suffered from “a non-specific personality disorder” and recounted — again citing the Libyan government as its source — a history of drug addiction and drug dealing and accusations of murder and armed assault.  In 1993, the document asserts, Mr. Qumu escaped from a Libyan prison, fled to Egypt and went on to Afghanistan, training at a camp run by Mr. bin Laden. At Guantánamo, Mr. Qumu denied knowledge of terrorist activities. He said he feared being returned to Libya, where he faced criminal charges, and asked to go to some other country where “You (the United States) can watch me,” according to a hearing summary.  Nonetheless, in 2007, he was sent from Guantánamo to Libya and released the next year in an amnesty for militants.  Colonel Qaddafi has cited claims about Mr. Qumu’s past in statements blaming Al Qaeda for the entire Libyan uprising. American officials have nervously noted the presence of at least a few former militants in the rebels’ ranks.  The walls of buildings along the road into Darnah are decorated with the usual anti-Qaddafi and pro-Western slogans, in English and Arabic, found all over eastern Libya. But there are notable additions: “No Qaeda” and “No to Extremism.”  Darnah has reason to be touchy. The town has a long history of Islamic militancy, including a revolt against Colonel Qaddafi’s rule led by Islamists in the mid-1990s that resulted in a vicious crackdown. Activists from here are credited with starting the Libyan Islamic Fighting Group, which later announced that it was affiliating with Al Qaeda, and which sent militants like Mr. Qumu to fight in Afghanistan.  Most famously, though, Darnah has a claim to being the world’s most productive recruiting ground for suicide bombers. An analysis of 600 suicide bombers in Iraq by the Combating Terrorism Center at West Point found that of 440 who listed their hometowns in a recruiting roster, 52 were from Darnah, the most of any city, with Riyadh, Saudi Arabia, 40 times as populous, as the next biggest source, sending 51.  In addition to Mr. Qumu, local residents say the Darnah Brigade is led by Abdul-Hakim al-Hasadi, another Libyan thought to be a militant who was in Afghanistan during the Taliban’s rule, when Al Qaeda had training camps there.  Mr. Qumu did not turn up for a promised interview last week, but Mr. Hasadi did, in crumpled fatigues with a light beard and a lazy left eye, perpetually half-closed. He denied that Mr. Qumu was in his group, recently renamed the Martyrs of Abu Salim Brigade, after a prison in Tripoli where 1,200 inmates were slaughtered in 1996. Two of Mr. Qumu’s sons are in his brigade, he said.  “I don’t know how to convince everyone that we are not Al Qaeda here,” Mr. Hasadi said. “Our aim is to topple Qaddafi,” he added. “I know that you will never believe me, but it is true.”  For now, Western observers in Benghazi, the temporary rebel capital 180 miles from here, seem content to accept those assurances. “We’re more worried about Al Qaeda infiltration from outside than the indigenous ones” one said. “Most of them have a local agenda so they don’t present as much as a threat to the West.”  Rod Nordland reported from Darnah, and Scott Shane from Washington. Kareem Fahim contributed reporting from Benghazi, Libya.  This article has been revised to reflect the following correction:  An earlier version of the picture caption with this article erroneously identified Abdul-Hakim al-Hasadi as Abu Sufian Ibrahim Ahmed Hamuda bin Qumu.  An earlier version of the picture caption with this article erroneously identified Abdul-Hakim al-Hasadi as Abu Sufian Ibrahim Ahmed Hamuda bin Qumu.
The GuantÃ¡namo assessment of a former Libyan detainee uses Libyan intelligence, but now that former detainee is a rebel trying to oust Libyaâs leader.