A couple of months ago, Newsweek had an interview with former FBI agent Ali Soufan, who was involved in the USS Cole bombing investigation and was taken off detainee interrogations after 9/11 due to the detainees being tortured.
I found this passage, about an argument Soufan had with CIA officials and contractors about (not) torturing Abu Zubaida in Thailand, to be most interesting:
As Soufan tells the story, he challenged a CIA official at the scene about the agency’s legal authority to do what it was doing. “We’re the United States of America, and we don’t do that kind of thing,” he recalls shouting at one point. But the CIA official, whom Soufan refuses to name because the agent’s identity is still classified, brushed aside Soufan’s concerns. He told him in April 2002 that the aggressive techniques already had gotten approval from the “highest levels” in Washington, says Soufan. The official even waved a document in front of Soufan, saying the approvals “are coming from Gonzales,” a reference to Alberto Gonzales, then the White House counsel and later the attorney general. (A lawyer for Gonzales declined to comment.)