Mandy Patinkin abruptly left the show in 2007, just as his character abruptly quit from the BAU, due to emotional distress. In 2012, Patinkin opened up about why he left stating that the show "was very destructive to my soul and my personality. After that, I didn't think I would get to work in television again." Immediately after Gideon's departure, Aaron Hotchner (Thomas Gibson) is appointed unit chief. When Hotchner also leaves the BAU, the position is given to Emily Prentiss (Paget Brewster), then temporarily to Jennifer Jareau (A. J. Cook), until Prentiss again becomes chief and remains so for the duration of the series. In season ten, Gideon is murdered off-screen by serial killer Donnie Mallick (Arye Gross).
