Original cast member Shemar Moore will be making a guest appearance in the season finale of CBS' Criminal Minds, reprising his role as Derek Morgan. Moore left the series almost a year ago, but will return to help bring the twelfth season to a close. In the finale, Morgan will provide the Behavioral Analysis Unit (BAU) with a lead in their ongoing investigation of Mr. Scratch, a serial killer and escaped convict who has caused havoc throughout the season. Mr. Scratch has targeted the BAU, causing one team member, Aaron Hotchner, to enter the Witness Security Program with his son due to being stalked by the killer. Shemar Moore's return comes after his recent addition to the cast of the CBS pilot S.W.A.T., a show inspired by the 2003 film and directed by Justin Lin.