Arthur Mitchell, often referred to as the "Trinity Killer," is a fictional character and the main antagonist of the fourth season of the Showtime TV series Dexter. Mitchell is a serial killer who presents himself as an unassuming church deacon and family man. FBI agent Frank Lundy (Keith Carradine) dubs him the "Trinity Killer" because of a recurring pattern of three killings based on traumatic events during Arthur's childhood. In the series, Mitchell is portrayed by John Lithgow.
Lithgow's performance of Mitchell was widely praised, with Lithgow winning a Golden Globe Award and a Primetime Emmy Award for his performance. In 2016, Rolling Stone ranked him #34 of their "40 Greatest TV Villains of All Time".[1]IGN ranked him #57 of the "Top 100 Villains".[2]