What is an Unsub?

Mary McMahon
Mary McMahon

In law enforcement terminology, an “unsub” is an unknown subject of an investigation. This term has been popularized by a number of crime series on television, making many civilians aware of it. Not all law enforcement agencies refer to unknown subjects as unsubs, with usage of the term varying depending on the agency involved and the region in which it is located.

Woman with hand on her hip
Woman with hand on her hip

Often, a law enforcement agency will publish information about an unsub in the hopes that members of the general public can identify the subject, making it easier to track him or her down. The agency may distribute a press release which includes photographs of the subject, along with a physical description culled from people who witnessed the crime under investigation or interacted with the subject. By publicizing information, the agency can sometimes receive a tipoff from someone who actually knows the subject, or has seen the subject along his or her travels.

There are a number of reasons for a suspect in a criminal case to remain unknown. While trace evidence can be used to identify many suspects, sometimes it takes a long time to process material gathered from a crime scene, and the agency may want to act quickly to apprehend the subject. In other cases, trace evidence turns up no useful information because the subject is not in criminal databases, or the evidence is compromised in some way.

Law enforcement agencies usually want to act quickly when a crime occurs because the shorter the lead time, the more likely it is that the criminal will be apprehended. By publishing information about an unsub, the agency can hopefully create a form of dragnet, with hotel staff, gas station attendants, and others being aware that they should call law enforcement if they see someone who resembles the unsub.

The other reason for publishing a request for information about an unsub is associated with public relations. Members of a community often become restless or concerned if they cannot see visible action on the part of a law enforcement agency, so by involving the public in the search for the ubsub, the agency shows that it is making progress on the case.

If you are shown a pamphlet or poster about an unsub, read it closely and take note of the identifying features. You should also be aware that some ubsubs are considered dangerous; if a poster tells you that someone is believed to be armed, for example, you should not try to apprehend or stop the ubsub yourself.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


It's ironic really. That term "unsub" being used by "Criminal Minds" is an attempt make them sound all cutting edge and high and mighty just like the characters on the show. Most of them are portrayed as self-important, jack-weed, know-it-alls so it fits.


Stephen James (author of Patrick Bowers books) uses this term in a mocking fashion a few times. When I saw the show and heard it I was like...wow, there really is a TV show that uses the unterm!


I seriously doubt any agency actually uses that stupid term.


Law enforcement doesn't use unsub. That's a made up word for TV, just like when cops on TV say "freeze!"


The term Unsub is used regularly in the TV series "Criminal Minds", a show that examines behavioral analysis.


Does anyone really use this word in real life?

Get real.

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