Dexter is an American crime drama television series that aired on Showtime from October 1, 2006, to September 22, 2013. Set in Miami, the series centers on Dexter Morgan, a forensic technician specializing in blood spatter analysis for the fictional Miami Metro Police Department. Dexter leads a secret parallel life as a vigilante serial killer, hunting down murderers who have not been adequately punished by the justice system due to corruption or legal technicalities. The series enjoyed mostly positive reviews throughout its run. The first four seasons were widely praised, but reception dropped considerably as the series progressed.