Editing KUBARK Counterintelligence Interrogation Review: Observations of an Interrogator (section)

===Joint Suspects===
If two or more interrogation sources are suspected of joint complicity in acts directed against U.S. security, they should be separated immediately. If time permits, it may be a good idea (depending upon the psychological assessment of both) to postpone interrogation for about a week. Any anxious inquiries from either can be met with a knowing grin and some such reply as, “We’ll get to you in due time. There’s no hurry now.”81

The primary difference between these two approaches is that in the first the source is presented with evidence — largely implicit — that other, unnamed, unknown (to the source), and as yet unseen detainees have provided information that reflects negatively upon him, while in the second scenario the interrogator refers directly to damaging information gathered from other detainees known to the source.

Leveraging one source against another is a common police tactic (the central idea of the classic “prisoner’s dilemma”) and is especially useful when dealing with sources who have limited or no training in resistance strategies. With sufficient validated intelligence supporting him, the interrogator can effectively present information to source A that was allegedly (and plausibly) provided by source B. The wedge thus placed, in conjunction with time and careful orchestration, can be effective in eliciting progressively more information independently from each source.

79 A radioactive dispersal device is often referred to in the media and in popular literature as a “dirty bomb.”
80 KUBARK, 67.
81 KUBARK, 70.