Unsub stands for "UNknown SUBject". It is used to refer to a suspect in a criminal investigation. The subject is usually suspected of a specific crime; serial killing, rampage killing, arson, etc. The term "unsub" is used by the BAU team as a code-name for the criminals they investigate on Criminal Minds. This process is repeated with the BAU team featured in Suspect Behavior and the International Response team featured in Beyond Borders. File:REAL ONES.jpg