"When I spoke to ABC News in December 2007 I was aware of Abu Zubaydah being waterboarded on one occasion," said Kiriakou. "It was after this one occasion that he revealed information related to a planned terrorist attack. As I said in the original interview, my information was second-hand. I never participated in the use of enhanced techniques on Abu Zubaydah or on any other prisoner, nor did I witness the use of such techniques."
A federal judge in New York is currently considering whether or not to make public the written logs of the interrogation sessions.
The tapes were destroyed by the CIA, but the written logs still exist, although the CIA is fighting their release.
A CIA spokesperson declined to comment for this report, except to note that the agency's terrorist interrogation program was guided by legal opinions from the Department of Justice.
Matthew Cole is a freelance national security reporter. His book, about the CIA rendition program, will be published later this year by Simon & Schuster.
This post has been updated.