Shortly after the Sept. 11, 2001, terrorist attacks, detainees in the CIA's secret prison network told interrogators about an important courier with the nom de guerre Abu Ahmed al-Kuwaiti who was close to bin Laden. After the CIA captured al-Qaida's No. 3 leader, Khalid Sheikh Mohammed, he confirmed knowing al-Kuwaiti but denied he had anything to do with al-Qaida.
In 2002 and 2003, interrogators first heard about a Qaeda courier who used the nom de guerre Abu Ahmed al-Kuwaiti, but his name was just one tidbit in heaps of uncorroborated claims.
After the capture in March 2003 of Mr. Mohammed, the chief planner of the Sept. 11, 2001, attacks, he was subjected to the most harrowing set of the so-called enhanced measures, which included slamming prisoners into walls, shackling them in stress positions and keeping them awake for as long as 180 hours. Like two other prisoners, he was subjected to waterboarding.
A diplomatic source told CNN that the courier who was in close contact with Osama bin Laden and who eventually led the United States to him was a Kuwaiti named Abu Ahmad.