A legal doctrine that says police may lie to suspects during interogations so long as an innocent person would not be affected. For example, the police could say that they had found a bloody fingerprint when they had not. The innocent person would know that they were lying, but the guilty would not be sure. A very effective technique, and one of the main reasons why defense lawyers exist.
See also Code 9, Community Policing, Hook N Book and Terry Stop.
This bit of jargon has been viewed 12,414 times.