Mutt and Jeff interrogation techniques
Mutt and Jeff interrogation techniques, often called good cop bad cop, involve an interrogation technique employing at least two interrogators, one of which plays the "irate tough guy" and the other the "sympathetic soul there to help."  The "bad cop" engenders fear in the prisoner, as a subset of fear up interrogation technique (e.g. Pride and Ego Down interrogation techniques), and intends to coerce information. From the perspective of the prisoner, the "good cop" is noncoercive and trying to build rapport, although the underlying interrogation plan involves psychological coercion. The friendly interrogator is using a type of incentive, offering the subject an escape from the hostile questioner.
The method was described by Phifer in the Guantanamo guidance, with the caveat that some nations might regard the method, used against prisoners of war, to be a violation of Article 13 of the Third Geneva Convention, "prisoners of war must at all times be protected, particularly against acts of violence or intimidation and against insults and public curiosity". The guidance, however, pointed out that the policy in force was that Guantanamo prisoners were not subject to the Geneva protections, but warned against a political liability. 
- Chris Mackey & Greg Miller (2004), The Interrogators: inside the secret war against al Qaeda, Little, Brown & Co., ISBN 0-316-87112-5, p. 480
- Diplomatic Conference for the Establishment of International Conventions for the Protection of Victims of War, held in Geneva from 21 April to 12 August, 1949 (12 August 1949), Geneva Convention relative to the Treatment of Prisoners of War, U.N. High Commissioner for Human Rights
- Jerald Phifer (October 11, 2002), Memorandum for Commander, Joint Task Force 170: Request for Counter-Resistance Strategies, Joint Task Force 170, Department of Defense