Jordana Spiro is the latest guest star to join season six of Showtime’s award-winning serial killer drama “Dexter.” The pretty 34-year-old will play a religious cult member under the spell of its homicidal leader (Edward James Olmos).

The synopsis for the show’s new season reads:

Dexter Morgan spent Season Five atoning for the death of his wife, Rita. He committed to being a part of her children’s lives and entered into a deep, passionate relationship with Lumen, unlike anything he’d ever had before.

But Dexter’s need to kill overpowers his desire for human connection. And now that one person knows the truth about him, and a few others are close, how much longer will America’s favorite serial killer be able to keep his dark side a secret?

Additional guest stars include Colin Hanks (Lucky), MC-turned-actor Mos Def, Mariana Klaveno (“True Blood”) Molly Parker (“The Firm”), Josh Cooke (Quarantine 2: Terminal), Billy Brown (Cloverfield), Brea Grant (“Heroes”) and Latin stunner Aimee Garcia (“Trauma”).

Spiro’s genre creds include an episode of “Buffy the Vampire Slayer” and a starring role in the From Dusk Till Dawn home-video sequel From Dusk Till Dawn 3: The Hangman’s Daughter. She will next be seen opposite Nicolas Cage and Nicole Kidman in director Joel Schumacher’s home-invasion thriller Trespass.