Lagouranis's tools included stress positions, a staged execution and hypothermia so extreme the detainees' lips turned purple. He has written an account of his experiences in a book, "Fear Up Harsh," which has been read by the Pentagon and will be published this week. Stephen Lewis, an interrogator who was deployed with Lagouranis, confirmed the account, and Staff Sgt. Shawn Campbell, who was Lagouranis's team leader and direct supervisor, said Lagouranis's assertions were "as true as true can get. It's all verifiable." John Sifton, a senior researcher for Human Rights Watch, said the group investigated many of Lagouranis's claims about abuses and independently corroborated them.

"At every point, there was part of me resisting, part of me enjoying," Lagouranis said. "Using dogs on someone, there was a tingling throughout my body. If you saw the reaction in the prisoner, it's thrilling."