John Bruce Jessen is an American psychologist who, with James Elmer Mitchell, created the so-called "enhanced interrogation techniques" that were used in the interrogation and torture of CIA detainees and outlined in the United States Senate Select Committee on Intelligence's report on CIA torture. In that report, he was mentioned under the pseudonym "Hammond Dunbar." His company, Mitchell Jessen and Associates, earned US$81 million for its work.

On October 13, 2015 the American Civil Liberties Union filed a lawsuit against James Mitchell and Bruce Jessen on behalf of Mohamed Ahmed Ben Soud, Suleiman Abdullah Salim, and the estate of Gul Rahman, three former detainees who were subjected to the interrogation methods they designed. The suit alleges that the defendants' conduct constituted torture and cruel, inhuman, and degrading treatment; non-consensual human experimentation; and war crimes – "all of which are violations of 'specific, universal, and obligatory' international law norms, as evidenced by numerous binding international treaties, declarations, and other international law instruments". A trial was set for June 2017.[18] On July 28, 2017, U.S. District Judge Justin Lowe Quackenbush denied both parties' motions for summary judgment, noted that the defendants are indemnified by the United States government, and encouraged the attorneys to reach a settlement before trial. A settlement was reached in August 2017.