Academy Award-nominated and Emmy, Tony and Golden Globe award-winner John Lithgow will take on one of his most intense and intriguing roles to date portraying Miami's latest serial killer in Showtime's top-rated drama series "Dexter." Lithgow will be featured in all 12 episodes of season four which are scheduled to premiere Sunday, September 27th on Showtime.

Lithgow will play Walter Simmons, an unassuming, mild-mannered suburbanite who has been living a dual life as one of America's most prolific and deadliest serial killers. Dubbed the "Trinity Killer" because of his proclivity to kill in three's, he relocates to Miami after being tracked by F.B.I. Special Agent Frank Lundy (Keith Carradine). Brought on to assist in the investigation of Miami's latest serial killer, Dexter Morgan (Michael C. Hall) becomes fascinated with "Trinity's" unique killing methods and his ability to evade capture for almost three decades.

"Dexter" stars Michael C. Hall as a complicated and conflicted blood-spatter expert for the Miami police department who moonlights as a serial killer. The show also stars Julie Benz, Jennifer Carpenter, C.S. Lee, Lauren Vélez, David Zayas, and James Remar.