Informant

An informant is someone who provides information to one or more parties, usually in a secretive way, and always with some measure of benefit to the one giving the information. This usually takes the form of criminals who provide information to law-enforcement agencies in exchange for leniency with regards to whatever crimes they may otherwise be guilty of.

An obscure example of an informant is a man named Flea, who appeared in issues of Luke Cage, Hero for Hire, published by Marvel Comics. Flea provided Luke Cage with information that enabled him to track a shipment of heroin that was used by Willis Stryker in order to frame him.