Dexter (2006)

Meet Dexter Morgan. By day he's a blood spatter pattern expert for the Miami Metro police department. But by night - he takes on an entirely different persona: serial killer. But Dexter isn't your average serial killer as he only kills people who fit a very prolific and precise "moral code" taught to him by his late father Harry (he didn't kill Harry, honest), and developed very thoroughly throughout each kill. While dealing with his daily activities and his boss, Sgt. Doakes, the one man who may or may not know the truth about his after-hours activities, he is given a friendly message by a guy referred to only as "The Ice Truck Killer" - a crime scene where there is no blood. This shocking discovery turns Dexter's world completely upside down. The Ice Truck Killer wants Dexter to play his game and Dexter is very eager to take on this cat-and-mouse chase throughout Miami.