The man who waterboarded Khalid Sheikh Mohammed, the so-called mastermind of the Sept. 11 terror attacks, told Megyn Kelly on Tuesday that the CIA's program of using enhanced interrogation techniques did not amount to torture, despite recent accusations in a Senate-issued report.

"If it was torture, I would be in jail," James Mitchell said on "The Kelly File." "This thing was investigated over and over. I was told by the highest law enforcement agency in the land that we were going to walk right up to the edge of the law, and that all of the things we had included in that list were legal."

Mitchell, a former Air Force psychologist, said in the days following the Sept. 11 attacks, the country was gripped with fear that new attacks were forthcoming and both the public and the U.S. government were desperate to prevent them.

"(The CIA) had ongoing information to suggest that (terrorists) were trying to smuggle nuclear weapons into the U.S.," Mitchell said. "There was all this anthrax stuff going on, there was credible evidence to suggest that there was another wave of attacks coming and we couldn't have it happen."

Mitchell added: "They tried to decapitate us last time, they tried to destroy our civilization. And people were clamoring to do everything and anything they could that was legal, to take it right up to the line and save American lives. Because that's what our government is supposed to do: save American lives."

Mitchell, who said he found waterboarding "repulsive at times" but said he did it out of a duty to protect the U.S., criticized the Senate report, saying it's "easy" in hindsight to second-guess the tactics used after 9/11, more than 13 years after the attacks.

"In my view, the CIA analysts and the CIA targeters are incredible," he said. "To do this, to besmirch them, I think, is beyond the pale."