First Look: William Petersen Returns to CSI... But There's a Catch

Is CSI‘s Gil Grissom dusting off his forensics tools and getting back into the Vegas crime-fighting game? William Petersen returned to the set of the long-running CBS crime drama this week for a very special reason, and we’ve got the pictures to prove it.

CSI reached yet another landmark in its 11-year run on Tuesday, this time ringing in their 250th episode. Of course, Petersen was on hand for the cake and confetti, enjoying the festivities as both a longtime castmember and an executive producer on the series. Series stars Marg Helgenberger and Laurence Fishburne were also in the mood for a little cake-cutting fun.

Take a peek at the first look photos below:

Petersen, who exited CSI as a regular in 2008, returned for a brief “surprise” cameo last month.

CSI‘s 250th episode airs Thursday, May 12 on CBS.