The issue of how far America should go in interrogating suspects gained renewed urgency when President-elect Donald Trump said while campaigning he would "bring back a hell of a lot worse than waterboarding" for suspected jihadists, though he later dialed back his rhetoric.
James Mitchell, along with his colleague John "Bruce" Jessen, worked under a CIA contract to advise on the use of waterboarding and other techniques.
Speaking at a Washington think tank, Mitchell insisted the information gleaned by waterboarding several suspects including Khalid Sheikh Mohammed (KSM) - the alleged mastermind of 9/11 - was vital and helped save US lives.
"They need to ask themselves -- and I would ask President-elect Trump this -- what are you going to do when you have credible evidence, like the CIA did, of another pending catastrophic attack ... And the person you are interrogating isn't responding?"
Also Read
Mitchell claims to have interrogated 14 of the most "high-value" detainees in US custody, including KSM and Abd al-Rahim al-Nashiri, suspected of carrying out an attack on the destroyer USS Cole in the port of Aden that killed 17 US military personnel in October 2000.
In an interview with the New York Times, Trump recounted how Mattis had said that winning a prisoner's trust is a far more effective way of prying information.
"'Give me a pack of cigarettes and a couple of beers and I'll do better,'" Trump said Mattis had told him.
But Mitchell insisted rapport-building approach doesn't always work, and said the United States must develop "some form of legal coercion to move (suspects) along so you can start using social influence to get them talking."
Two former detainees are suing Mitchell and Jessen over their "barbaric" methods.
Mitchell's appearance came as he is publicizing his book, "Enhanced Interrogation: Inside the Minds and Motives of the Islamic Terrorists Trying To Destroy America.
Disclaimer: No Business Standard Journalist was involved in creation of this content