CSI: Crime Scene Investigation (season 4) CSI: Crime Scene Investigation (season 4) The fourth season of "" premiered on CBS on September 25, 2003 and ended May 20, 2004. The series stars William Petersen and Marg Helgenberger. Nick accidentally leaks information to a news reporter ("Assume Nothing"), and Catherine tries to discover how a body ended up in a bathtub ("All for Our Country") during the fourth season of "CSI". Supervised by Grissom and Willows, the Las Vegas CSIs are tasked with investigating the bizarre, the unlikely, and the unprecedented, including a disappearing gun ("Homebodies"), the death of a baby during a heatwave ("Feeling the Heat"),
CSI: Crime Scene Investigation (season 9) and Wendy attend a sci-fi convention ("A Space Oddity"). William Petersen and Gary Dourdan both depart the main cast, and are replaced by Lauren Lee Smith and Laurence Fishburne, respectively. Jorja Fox recurs. <onlyinclude></onlyinclude> CSI: Crime Scene Investigation (season 9) The ninth season of "" premiered on CBS on October 9, 2008 and ended May 14, 2009. The series stars William Petersen, Marg Helgenberger and Laurence Fishburne. As the team grieve for their fallen colleague ("For Warrick"), Grissom makes a life changing decision ("One to Go"), during the ninth season of "CSI". Also this season, Sara investigates the death of