Undercover tactics provide police information and arrests not otherwise available, given the absence of a complainant, the skill and tight organization of a criminal group, or the conditions under which a crime is committed. Although the deterrent effect of undercover police work has not been adequately documented, in theory it may deter some offenders, since a potential victim, client, or supplier could be an undercover police person. Invasion of privacy, possible false testimony, corruption, and entrapment are some of the potential abuses of undercover police work. The acceptability of police undercover tactics should hinge on the nature of the offense, the context, and the nature of police undercover behavior. In general, undercover activity is most acceptable when used against felonies and where there is a complainant other than the state. Where decoys are used passively in response to a proven crime pattern and become victims, undercover work is appropriate; however, when the alleged offense is a misdemeanor or involves consenting adults exchanging services, undercover tactics are not appropriate. When no verification of an undercover operative's account is possible or when the tactics actively facilitate criminal behavior, undercover work should be disallowed. Standards could be enforced by requiring a court's warrant for each undercover operation or by having training and close supervision of undercover police according to clear departmental standards.