In analyzing the social context of normal police lies, lies are defined as speech acts which the speaker knows are misleading or false, are intended to deceive, and where evidence to the contrary is known to the observer. Lies are relative to a moral context and to what an audience will accept. Lies include excuses which deny full responsibility for an act but acknowledge immorality and also justifications which accept responsibility but deny blameworthiness. An 18-month field study of a large urban police force is reported that indicates how and why some types of lies are rewarded. The focus is on two kinds of lies: (1) case lies, recognized stories an officer uses in the courtroom or on paper to facilitate the conviction of a suspect; and (2) cover stories, lies an officer tells in court, to supervisors, and on the job with the aim of providing a verbal shield or mitigation in the event of discipline. An example of a refusal to lie is used to illustrate some of the limits on lying as well as organizational factors in lying. Some implications for official lying are also noted. 45 references and 11 notes (Author abstract modified)