Couch had a friend, from his Marine Corps service, Michael Horrocks, who was a co-pilot of one of the jets hijacked on September 11, 2001. Couch is reported to have returned to service, following the attacks, so he could "get a crack at the guys who attacked the United States."
Service as a prosecutor at the Guantanamo Military Commissions
Couch was assigned to serve as one of the prosecutors of Mohamedou Ould Slahi in his case before a military commission at the Guantanamo Bay detention camp. In 2003 Couch withdrew from Slahi's prosecution team because he believed he was asked to use evidence obtained through means of coercive interrogation that violated the Uniform Code of Military Justice, U.S. laws, and the United States' treaty obligations. He said he believed that Slahi was guilty but felt that evidence derived from torture was inadmissible in court.
On July 19, 2007 the Globe and Mail quoted an email from Couch: "I would not characterize my decision re: Slahi as 'comfortable' but in retrospect would still make the same career decision," His resignation received national media coverage, including a long article in 2007 in the Wall Street Journal. It said that he had argued with Robert L. Swann, the Chief Prosecutor.
On February 26, 2009, the Virginia Law Weekly also profiled Couch. In a lecture, Couch said: "In the fall of 2003, something caused Slahi to start singing like Beyonce."[clarification needed] Couch was later to learn that Slahi had been put under "special projects" interrogation plan authorized by the Office of the Legal Counsel in consultation with the CIA, in which specific enhanced interrogation techniques, commonly considered torture, were used.
Testimony before Congress
Couch was scheduled to testify before the House Judiciary Committee on November 8, 2007. An e-mail from the Department of Defense's General Counsel, William J. Haynes, II, informed him on November 7, 2007: "... as a sitting judge and former prosecutor, it is improper for you to testify about matters still pending in the military court system, and you are not to appear before the committee to testify tomorrow."
- Jess Bravin (March 31, 2007). "The Conscience of the Colonel". Wall Street Journal. Retrieved 2007-04-11.
- Jess Bravin (March 31, 2007). "The Conscience of the Colonel". mirror of the Wall Street Journal article. Retrieved April 11, 2007.
- "Three tales of Gitmo 'taint'". Monterey Herald. April 7, 2007. Retrieved 2007-04-11.
- Robert Scheer (April 4, 2007). "Leave Your Morals at the Border". The Nation. Retrieved 2007-04-11.
- Scott Horton (April 2, 2007). "Colonel with a Conscience". Harpers. Retrieved 2007-04-11.
- Colin Freeze (July 17, 2007). "Tortuous tale of Guantanamo captive: A declassified transcript reveals how a former Montreal resident crossed four continents and the paths of key al-Qaeda personalities". Globe and Mail. Retrieved 2007-07-20.
- Harry Crump (2009-02-27). "Military Prosecutor Recounts Guantanamo Bay Case". 61 (19). Virginia Law Weekly. Retrieved 2009-02-26. mirror
- "U.S. Marine lawyer barred from testifying". United Press International. November 8, 2007. Retrieved 2007-11-08.
- Laurie Kellman (November 8, 2007). "Waterboarding is torture, ex-Navy interrogator says". Houston Chronicle. Retrieved 2007-11-08.
- "House Panel Gets Earful On Waterboarding: In Spite Of Bickering In D.C., Experts Say Interrogation Method Is Torture, Must Never Be Used". CBS News. November 8, 2007. Retrieved 2007-11-08.
- Vivian Giang (2009-03-26). "Former military prosecutor speaks about torture techniques". The Red and Black. Retrieved 2009-03-26.
- (German) Widerstand gegen Folter Berliner Zeitung, 16. November 2009