The acclaimed actress will star in Season 2 of the USA crime drama, following in the steps of Jessica Biel, who will step back but continue to serve as an executive producer.
Bill Pullman will return to headline as the troubled Detective Harry Ambrose, who is lured back to his rural New York hometown to investigate a new crime: parents murdered by their 11-year-old son, with no apparent motive. As Ambrose delves into the situation, he gets pulled into the hidden darkness lurking in his hometown.
Coon (currently appearing in "Avengers: Infinity War") will play Vera, a "formidable, mysterious woman who struggles between upholding the ideals of the community she leads and fulfilling her own desires."
Also joining the cast in Season 2 are Natalie Paul ("The Deuce") as a detective-in-training who calls Ambrose for help and Hannah Gross ("Mindhunter") as the former's missing best friend.
"The Sinner" was planned as a one-off limited series, though creator Derek Simonds remained open to continuing it as an anthology.
It's unclear if Biel will reprise her role as Cora Tannetti, who was sentenced to a psychiatric facility in the Seaosn 1 finale."We're starting fresh again," Biel told Entertainment Weekly last year. "I will definitely be involved in some way! I hope somebody writes me into the show, if we can figure it out. We will figure it out if it's possible, but we want to be authentic to the show."