Dexter's Trinity Killer Prequel Series Progressing With John Lithgow Returning as Narrator

Showtime's planned spinoff will explore the origins of Arthur Mitchell, with scripts completed but the series awaiting further development decisions.

The Trinity Killer prequel series will focus on the early life of Arthur Mitchell, Dexter's most infamous adversary, and how he became a serial killer.
John Lithgow, who originally portrayed the character, will narrate the series as the voice of his younger self, similar to Michael C. Hall's role in Dexter: Original Sin.
Showrunner Clyde Phillips and writer Scott Reynolds, veterans of the original Dexter series, are co-creators and executive producers of the project.
Scripts for the prequel have been completed, but Showtime is prioritizing other Dexter-related projects, including Dexter: Resurrection, set to premiere in June 2025.
The success of Dexter: Original Sin, which has garnered strong viewership, may influence Showtime's decision to move forward with the Trinity Killer prequel.