Mark Bowden has an account in the Atlantic (unfortunately accessible by subscription only) describing how Task Force 145 interrogators or "gators" at Balad Airbase got prisoners in their custody to answer the question "where is Zarqawi?", the answer to which led directly to the AQI chief's demise. The drama revolved around two of Zarqawi's captured lieutenants, one of whom was not who he seemed to be yet guarded an important secret. The time left to the interrogators was short; the detainees were scheduled to be processed out to another holding facility. Task Force 145 had to assemble all the pieces of the puzzle and separate the misdirection from the truth.
There was no question of using coercive methods. But the interrogators could still build an alternative reality in the prisoners minds which they peopled with vague fears, plots, promises and imaginary drama. And in the make believe world that they shared with the prisoners the interrogators would have to find the answer to their questions.
Still, even though he clearly relished his "secret" sessions with Doc, Abu Haydr protected the men at the very top of the organization. The ploy played upon his belief that he was operating in a multilayered reality, and at a deeper level than those around him; the secrecy just reinforced the ruse that Doc was a high-level connection. In the middle of this process, Mary started questioning Abu Haydr with the older gator they called Tom, and Lenny continued on in separate shifts by himself.
In early June, after Doc told the prisoner he was at "90 percent," Abu Haydr promised to give up a vital piece of information at his next session. And he did.
"My friend is Sheikh al-Rahman," he told Mary and Tom.
Then the conversation began to revolve around one simple point: what was the role of the "small blue car"? It was the thread, a slender one. But at the end of it lay the quarry and they began pulling on it ever so carefully. Bowden describes the rest.