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Abruptly departed: David Caruso, right
Copyright © 2009, The Los Angeles Times
Played: Det. John Kelly
Lasted: One full season and four additional episodes
Why he left: Caruso demanded a hefty pay raise for the second season to match the amount of press he got. When producers balked, he left to pursue soon-to-be-DOA movie career.
How it went down on air: Kelly left the department in disgrace after many suspected that he withheld evidence in his girlfriend's murder trial.