Which actor does not play a killer on the U.S. TV series "Dexter"?

The actor who does not play a killer on the U.S. TV series "Dexter" is Keith Carradine. John Lithgow, Jimmy Smits, and Ray Stevenson each had a role as a killer during the series. Lithgow played Arthur Mitchell (aka The Trinity Killer), the main antagonist in season four of the Showtime series. Jimmy Smits was Miguel Prado, an Assistant District Attorney (ADA) in Miami and he is the third main antagonist (killer) that Dexter faces in season three. Stevenson's character on "Dexter" is Isaak Sirko (also known as Volk, Russian for "The Wolf"). Isaak was the leader of the Koshka Brotherhood and a businessman who ran various strip clubs, especially one in Miami called the Foxhole. He was one of the two main antagonists of season seven (alongside Maria LaGuerta).

In 2007 and 2009, Carradine played FBI Special Agent Frank Lundy on the TV series "Dexter". He was a high-ranking and illustrious FBI Special Agent who led police task forces dedicated to identifying and arresting serial killers.

Carradine (b. August 1949) is an actor who has had success on stage, film, and TV. He is also known for being a prominent member of a famous acting family. He made his film debut in a supporting role in Robert Altman’s "McCabe & Mrs. Miller". Later, he had success in film roles in "Thieves Like Us", "The Duellists", " The Long Riders", and roles in several of Alan Rudolph’s films. Besides his work on "Dexter", he was an Emmy nominee for his acting on the 1983 TV miniseries "Chiefs".