An informant is a person who provides privileged information about a person or organization to an agency. The term is usually used within the law enforcement world, where they are officially known as confidential or criminal informants (CI), and can often refer pejoratively to the supply of information without the consent of the other parties with the intent of malicious, personal or financial gain. However, the term is used in politics, industry and academia.
Informants are commonly found in the world of organized crime. By its very nature, organized crime involves many people who are aware of each other's guilt, in a variety of illegal activities. Quite frequently, confidential informants (or criminal informants) will provide information in order to obtain lenient treatment for themselves and provide information, over an extended period of time, in return for money or for police to overlook their own criminal activities. Quite often, someone will become an informant following their arrest.
Informants are also extremely common in every-day police work, including homicide and narcotics investigations. Any citizen who aids an investigation by offering helpful information to the police is by definition an informant.
The CIA has been criticized for leniency towards drug lords and murderers acting as paid informants, informants being allowed to engage in some crimes so that the potential informant can blend into the criminal environment without suspicion, and wasting billions of dollars on dishonest sources of information.
Informants are often regarded as traitors by their former criminal associates. Whatever the nature of a group, it is likely to feel strong hostility toward any known informers, regard them as threats and inflict punishments ranging from social ostracism through physical abuse and/or death. Informers are therefore generally protected, either by being segregated while in prison or, if they are not incarcerated, relocated under a new identity.
Corporations and the detective agencies that sometimes represent them have historically hired labor spies to monitor or control labor organizations and their activities. Such individuals may be professionals or recruits from the workforce. They may be willing accomplices, or may be tricked into informing on their co-workers' unionization efforts.
Paid informants have often been used by authorities within politically and socially oriented movements to weaken, destabilize and ultimately break them.
Informers alert authorities regarding government officials that are corrupt. Officials may be taking bribes, or participants in a money loop also called a kickback. Informers in some countries receive a percentage of all monies recovered by their government.
Lactantius described an example from ancient Rome involved the prosecution of a woman suspected to have advised a woman not to marry Maximinus II: "Neither indeed was there any accuser, until a certain Jew, one charged with other offences, was induced, through hope of pardon, to give false evidence against the innocent. The equitable and vigilant magistrate conducted him out of the city under a guard, lest the populace should have stoned him... The Jew was ordered to the torture till he should speak as he had been instructed... The innocent were condemned to die.... Nor was the promise of pardon made good to the feigned adulterer, for he was fixed to a gibbet, and then he disclosed the whole secret contrivance; and with his last breath he protested to all the beholders that the women died innocent."
Criminal informant schemes have often been used as cover for politically motivated intelligence offensives.
Jailhouse informants, who report hearsay (admissions against penal interest) which they claim to have heard while the accused is in pretrial detention, usually in exchange for sentence reductions or other inducements, have been the focus of particular controversy. Some examples of their use are in connection with Stanley Williams, Cameron Todd Willingham, Gerald Stano, Thomas Silverstein, Marshall "Eddie" Conway, and a suspect in the disappearance of Etan Patz.
Terminology and slang
Slang terms for informants include:
- cheese eater
- dog — Australian. May also refer to police who specialize in surveillance, or police generally.
- fink — this may refer to the Pinkertons who were used as plain-clothes detectives and strike-breakers.
- grass or supergrass, — rhyming slang for grasshopper, meaning copper or shopper and having additional associations with the popular song, "Whispering Grass", and the phrase snake in the grass.
- narc — a member of a specialist narcotics police force.
- nark — this may have come from the Romany term nak for nose or the French term narquois meaning cunning, deceitful and/or criminal.
- pursuivant (archaic),
- rat — informing is commonly referred to as "ratting."
- stool pigeon or stoolie 
- tell tale or tell-tale
List of famous informants
- James Carey, Irish terrorist
- Marvin Elkind, Jimmy Hoffa's former driver and subject of the 2011 Adrian Humphreys biography titled The Weasel: A Double Life in the Mob (Wiley, ISBN 0470964510)
- W. Mark Felt, a.k.a. "Deep Throat," former Deputy Director of the FBI
- Sammy Gravano, former underboss of the Gambino crime family
- Henry Hill, Lucchese crime family associate
- Frank Lucas, New York drug dealer turned informant
- Joseph Valachi, soldier in the Genovese crime family
- Salvatore Vitale, former underboss of the Bonanno crime family
- Freddie Scappaticci leading member of the Provisional IRA and year long British informant.
- Agent provocateur
- Aguilar–Spinelli test
- Hollywood blacklist
- Plea bargain
- Turn state's evidence
- United States Marshals Service
- Witness Protection Program
- The Weakest Link: The Dire Consequences of a Weak Link in the Informant Handling and Covert Operations Chain-of-Command by M Levine. Law Enforcement Executive Forum, 2009
- Pursuing strategic advantage through political means: A multivariate approach by DA Schuler, K Rehbein, RD Cramer – Academy of Management Journal, 2002
- Reading English for specialized purposes: Discourse analysis and the use of student informants by A Cohen, H Glasman, PR Rosenbaum-Cohen, J. Tesol Quarterly, 197
- Kid Who Sold Crack to the President by J Morley. Washington City Paper, 1989
- Government Corruption and the Right of Access to Courts by UA Kim. Michigan Law Review, 2004
- Private detective agencies and labour discipline in the United States, 1855–1946 by RP Weiss. The Historical Journal, 2009. Cambridge Univ Press
- Judicial Control of Informants, Spies, Stool Pigeons, and Agent Provocateurs by RC Donnelly – Yale Law Journal, 1951
- Thoughts on a neglected category of social movement participant: The agent provocateur and the informant by GT Marx – American Journal of Sociology, 1974
- Lactantius. "On the Deaths of the Persecutors".
- CIA Assets and the Rise of the Guadalajara Connection J. Marshall – Crime, Law and Social Change, 1991
- Role of the Rat in the Prison by HA Wilmer. Fed. Probation, 1965
- The Origin of fink "informer, hired strikebreaker" by William Sayers. A Quarterly Journal of Short Articles, Notes, and Reviews. Winter 2005 Cornell University
- Criminal classes: offenders at school by A Devlin. 1995
- The Intelligence War in Northern Ireland by K Maguire – International Journal of Intelligence and CounterIntelligence, Volume 4, Issue 2 1990 , pages 145–165
- Oxford English Dictionary, "A spy or informer, esp. for the police"
- Greer, Steven C., Supergrasses: a study in anti-terrorist law enforcement in Northern Ireland
- Chicano intravenous drug users: The collection and interpretation of data from hidden from Hidden Populations by R Ramos. 1990
- Prison patter: a dictionary of prison words and slang by A Devlin. 1996
- Some ethical dilemmas in the handling of police informers by C Dunnighan, C Norris – Public Money & Management, 1998
- Oxford English Dictionary, "A spy or informer, esp. for the police"
- Speaker and Structure in Donne's Satyre by NM Bradbury. Studies in English Literature, 1500–1900, 1985.
- Sociology of Confinement: Assimilation and the Prison" Rat" by EH Johnson. The Journal of Criminal Law, Criminology, and Police Science. 1961
- Reflections on the role of statutory immunity in the criminal justice system by WJ Bauer – Journal of Criminal Law. & Criminology, 1976
- Oxford English Dictionary, "A police informer"
- Instigated Crime by S Shaw – Alta. LQ, 1938
- Elevating the Role of the Informer: The Value of Secret Information. MW Krasilovsky. ABAJ, 1954
- On Truth and Lie in a Colonial Sense: Kipling's Tales of Tale-telling by A Hai – ELH, 1997
- Telling tales in school by A Minister. Education 3–13, 1990
- Prison ministry: hope behind the wall by Dennis W. Pierce – 2006