US TV
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WENN
The Emmy and Tony winner will be in all 12 episodes of the show's run, The Hollywood Reporter confirms.
The actor will star as Walter Simmons, a serial killer and nemesis to Michael C. Hall's Dexter Morgan character.
The show's producers have described Lithgow's character as an "unassuming, mild-mannered suburbanite who has been living a dual life as one of America's most prolific serial killers". The character has also been dubbed the 'Trinity Killer' for his proclivity to kill in threes.
Season four of Dexter premieres September 27.
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