Unsub

An unknown subject (commonly referred to as an unsub) is the original designation for any criminal at the first point of contact, pre-identification, used by the Behavioral Assessment Unit to classify criminals. They are designated into numbers (ex. UNS-007) and are often given nicknames (ex. UNS-007 is nicknamed The Fox). The BAU designates unsubs into three categories: Alpha, Beta and Zeta, with Alphas being the most dangerous.

Alpha
Alpha unsubs are the most dangerous type. They are known for their cruelty and brutality in which they commit murders. They are also known for the sheer number of murders they commit during their crime spree. If spotted, a civilian must avoid an Alpha unsub at all costs.

Ex. UNS-83 (The Boston Reaper), UNS-231 (Mr. Scratch), UNS-127 (The Unholy Matrimony)

Gamma
Gamma unsubs are the second-most dangerous type. They are also brutal killers; however, they do not take pleasure in their killings, nor do they seek to kill for the fun of killing, i.e., they are not sadists. Gamma unsubs are still a danger to the public, and should be avoided at all costs.