Dexter Season 5

Mild-mannered Dexter Morgan (Golden Globe winner Michael C. Hall) works for the Miami Metro Police Department as a blood-splatter analyst -- and moonlights as a murderer who only targets other killers, a moral code instilled in him by his adoptive father, Harry (James Remar). As Dexter channels his sociopathic urges into acts of vigilantism, his co-workers, friends and family remain blissfully unaware of his bloodthirsty alter ego.