Sonja Fleming / CBS
Abruptly departed: Laurence Fishburne
Played: Pathologist Raymond Langston, who replaced Gil Grissom (William Petersen) as the show's focal character.
Lasted: 2½ seasons (2008-11)
Why he left: Fishburne never disclosed his reasons for leaving but said he was still a fan of the show, despite not having watched it since his departure. Fans felt he never gelled in his role as Dr. Raymond Langston, and the forensics drama 12th season was downgraded from its Thursday showcase to Wednesday.
How it went down on air: Fishburne's "CSI" alter ego killed his ex-wife's kidnapper and tormenter and left the show on a dark note. The writers toiled on on story lines for the following season and soon replaced him with "Cheers" star Ted Danson.