CSI alum William Petersen is joining WGN America's atomic bomb series Manhattanas a series regular in Season 2, the network announced Thursday.

Petersen will play Col. Emmett Darrow, a religious and patriotic man who's the new ranking military officer at Los Alamos. The colonel feels that it's God's plan for him to usher in the atomic future and spread American values around the world.

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Peterson, who played Dr. Gil Grissom on CSI for nine seasons, joins Manhattan's existing cast, which includes John Benjamin Hickey, Daniel Stern and Olivia Williams.

Manhattan's second season will premiere later this year. Are you looking forward to meeting Petersen's character?