Dexter

Dexter is a drama on Showtime.

The title character is a man named Dexter Morgan, who works in the Miami Police Department forensics department... and is a serial killer.

Dexter only kills those that have committed murder, at least, though this line of work does cause problems for him. It tests his relationships with sister Debra and girlfriend Rita. As well as with the actual law, of course.

As a child, Dexter witnessed the bloody murder of his mother, which has affected him both professionally (as an expert on blood) and personally (as a serial killer with an inherent need to kill).