John Lithgow Lands Killer Role On Showtime’s Dexter

John Lithgow is joining the cast of Dexter, the network announced. Lithgow will appear in all 12 episodes of the show’s upcoming fourth season, playing Walter Simmons, Miami’s latest serial killer and Dexter’s new nemesis.

Simmons is described as an unassuming, mild-mannered suburbanite who has been living a duel life as one of America’s most prolific and deadliest serial killers, dubbed the “Trinity Killer” because he likes to kill in threes. He relocates to Miami after being tracked by FBI Special Agent Frank Lundy (Keith Carradine). Dexter is brought on to assist in the investigation and becomes obsessed by his skill and ability to evade capture for almost three decades.

The fourth season of Dexter premieres September 27 on Showtime.