He’s a serial killer who works for the police dept. as a blood spatter analyst.
Orphaned at the age of three and harboring a traumatic secret, Dexter was adopted by a Miami police officer named Harry Morgan, who recognized his sociopathic tendencies and taught him to channel his gruesome passion for killing and directing in a “constructive” way: by killing people who “deserve it”. Most have slipped through the justice system, due to loopholes and technicalities in the law or were never apprehended.

Its FANTASTIC!