In the law enforcement jargon, a suspect is a known person accused or suspected of committing a crime. Police and reporters in the United States often use the word suspect as a jargon when referring to the perpetrator of the offense (perp in dated US slang). However, in official definition, the perpetrator is the robber, assailant, counterfeiter, etc.—the person who committed the crime. The distinction between suspect and perpetrator recognizes that the suspect is not known to have committed the offense, while the perpetrator—who may not yet have been suspected of the crime, and is thus not necessarily a suspect—is the one who did. The suspect may be a different person from the perpetrator, or there may have been no actual crime, which would mean there is no perpetrator. - Source: Wikipedia
