To find Osama bin Laden, U.S. officials first had to find the man who served as his courier. But the operation that killed the al-Qaida leader has stirred up some controversy: Some of the information about the courier may have come as the result of harsh CIA interrogations.
NPR has learned that the courier was a Kuwait-born Pakistani who went by the name Abu Ahmed al-Kuwaiti. It was in his house that U.S. forces found and killed bin Laden.
A few of the detainee assessment documents that showed evidence about interrogations regarding bin Laden's courier network.
Documents from the Guantanamo detention camp show that prisoners there and at secret CIA facilities were interrogated over and over about bin Laden's courier network and Kuwaiti in particular.
One man scheduled to be transferred out of Guantanamo, for example, was recommended for continued detention in part because intelligence officials thought he had more information to provide about Kuwaiti.
Every statement was carefully recorded: that Kuwaiti had a guesthouse in Pakistan where he hosted visiting al-Qaida volunteers; that he arranged airline travel and passed along money from al-Qaida financiers; that he was assigned to teach one al-Qaida member to use email.
The Guantanamo documents describe Kuwaiti as a senior al-Qaida facilitator and courier. The footnotes reveal how — and when — this information was acquired.
Some of the first leads came from detainees who were interrogated while in CIA custody; this is where the controversy arises.
About a third of the CIA detainees were subjected to what the agency euphemistically called enhanced interrogation techniques.
"They range from something as innocuous as the 'attention grasp' or 'facial grasp,' you know, grabbing somebody by the lapels or grabbing them by the chin, to a variety of things that have to do with sleep or diet or stress positions," former CIA Director Gen. Michael Hayden said.
In the most extreme cases, detainees were subjected to waterboarding, in which they experience what it's like to drown.
Among those who provided information while under CIA control was Hassan Gul, a senior al-Qaida operative from Pakistan. According to the detainee documents, Gul told interrogators that Kuwaiti traveled with bin Laden. A senior U.S. official says the information Gul provided was key to identifying Kuwaiti as bin laden's courier.
But he may have provided it under stress.
A 2005 document indicates that Gul was one of the CIA detainees subjected to "enhanced interrogation techniques." He is now free.
Khalid Sheikh Mohammed, a mastermind of the Sept. 11 attacks and one of three CIA detainees subjected to waterboarding, indirectly confirmed information about Kuwaiti.
Criticism Of Methods
Critics of "enhanced interrogation techniques" say they are tantamount to torture, and they argue that intelligence gleaned from those interrogations is unreliable. They also point out that some of the most useful information that came from Mohammed and others was obtained only after the harsh interrogations ended.
Hayden says he wouldn't be surprised by that.
"I'm willing to concede the point that no one gave us valuable or actionable intelligence while they were, for example, being waterboarded," he said. "The purpose of the enhanced interrogation techniques was to take someone who was refusing to cooperate with us and to accelerate the process by which we would move from a zone of defiance to a zone of cooperation."
Moving a detainee from defiance to cooperation — essentially, breaking him.
But how do you know the information the detainee finally provided could not have been acquired some other way?
In an interview with NBC, current CIA Director Leon Panetta said harsh CIA interrogations were only one part of the intelligence-gathering process that led to bin Laden's courier.
"They used these enhanced-interrogation techniques against some of these detainees, but I'm also saying that the debate about whether we would have gotten the same information through other approaches, I think, is always going to be an open question," Panetta said.
And a hotly debated one, given that finding and killing bin Laden was as much an intelligence triumph as a military achievement.