Person of interest

"Person of interest" is a term used by U.S. law enforcement when identifying someone involved in a criminal investigation who has not been arrested or formally accused of a crime. It has no legal meaning, but refers to someone in whom the police are "interested," either because the person is cooperating with the investigation, may have information that would assist the investigation, or possesses certain characteristics that merit further attention.

While terms such as suspect, target, and material witness have clear and sometimes formal definitions, person of interest remains undefined by the U.S. Department of Justice.Unsub is a similar term which is short for "unknown subject" (used often, for example, in the TV show Criminal Minds). Person of interest is sometimes used as a euphemism for suspect, and its careless use may encourage trials by media.

With respect to terrorism investigations, Eric Lichtblau wrote in the New York Times: "Law enforcement officials say that the term simply reflects the new tactics required to fight terrorism. But some legal scholars say officials are trying to create a more benign public image, even as their power expands."

According to the New York Times:

The term has an ugly history; in the 1960s American law enforcement officials began creating secret dossiers on Vietnam War protesters, civil rights leaders and other persons of interest...The vaguely sinister term has been applied to targets of terrorism investigations, the chief suspect in the murder of the Baylor basketball player Patrick Dennehy and Steven J. Hatfill, the scientist who has figured prominently in the investigation into the 2001 anthrax attacks...Attorney General John Ashcroft is often credited with popularizing the person-of-interest label, having used it [in 2002] to describe Dr. Hatfill.

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Wikipedia