<EM>CSI: Crime Scene Investigation</EM> CSI: Crime Scene Investigation

After more than six seasons in Sin City, CSI: Crime Scene Investigation's top investigator is leaving Las Vegas. At least temporarily.

Beginning with this week's episode (airing tonight at 9 pm/ET, on CBS), William Petersen's grim Gil Grissom is going on sabbatical to deal with the frustrations that have been making it difficult for him to do his job. "We've seen Grissom suffering from burnout," explains executive producer Carol Mendelsohn. "Now he has an offer to teach a seminar at Williams College, which he finds enticing."

Grissom's break is coming about because Petersen himself wanted time off — to do a play in Providence, Rhode Island. And while both departures seem temporary, Grissom's will permanently change relationships in the CSI lab. "He's taught all of them so much, that he [now] realizes they've become his equals," adds Mendelsohn. "And he'll tell Warrick (Gary Dourdan) that he's the rock of the team now. It's a passing of the torch."

Speaking of torches, what about the one Grissom carries for Sara? According to Mendelsohn, his departure will cause tension in that relationship, the source of which will become clear in a future episode — when Grissom will try to make things right by "sending Sara (Jorja Fox) something. Fans may remember the last time he did that, it was a plant. So for longtime fans, this will have resonance."

For much more scoop on the second half of the TV season, pick up the "2007 Preview" issue of TV Guide, now on newsstands.

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