ⓘ Turn state's evidence

Turn state's evidence

ⓘ Turn states evidence

A criminal turns states evidence by admitting guilt and testifying as a witness for the state against his/her associate or accomplice, often in exchange for leniency in sentencing or immunity from prosecution. The testimony of a witness who testifies against co-conspirator may be important evidence.


1. History

In the United Kingdom and the Commonwealth realms, the term is to turn Queens or Kings evidence, depending on the gender of the reigning monarch. The term "turning approver" or "turn kings approver" was also historically used, and is still used in India and Pakistan; an approver "not only admitted his own guilt to a crime but also incriminated his accomplices both past and present" in exchange for avoiding a death sentence and obtaining a lesser penalty, such as life imprisonment or abjuration of the realm or improving prison conditions.

In American parlance, a defendant who agrees to cooperate with prosecutors and give information against co-conspirators often those with greater culpability is also said to flip.

Witnesses who have turned states evidence have been important in organized crime cases in the United States, such as those against the American Mafia. The first mafiosi who turned states evidence, such as Joseph Valachi and Jimmy Fratianno, did so in response to threats on their life from Mafia associates; later cooperators were motivated to cooperate in order to avoid heavy sentences, such as those provided for under the RICO Act. Some who turned states evidence were permitted to participate in the Witness Security Program WITSEC. Among the highest-ranking Mafia members to ever turn states evidence was Salvatore Gravano "Sammy the Bull", an underboss of the Gambino crime family who pleaded guilty to 19 murders and agreed to testify against family boss John Gotti. Gravano was sentenced to 20 years; Gotti was sentenced to life imprisonment in 1992. Joseph Massino was also the first boss of one of the Five Families in New York City to turn states evidence.

The incentives to turn states evidence, or to not to do so, are explored in the famous prisoners dilemma, created by Merrill Flood and Melvin Dresher.