By Jonathon Dornbush
August 03, 2015 at 08:59 PM EDT

Production is underway for the CSI two-hour send-off planned for this fall, and the stars of the special haven’t been shy about posting from behind the scenes.

Marg Helgenberger, who’s currently starring on CBS’ Under the Dome, posted two reunion photos from the CSI series finale set. The first, viewable above, reunites Catherine Willows (Helgenberger) and Gil Grissom (William Petersen). The second photo brought together five original characters: Willows and Grissom along with Sara Sidle (Jorja Fox), Greg Sanders (Eric Szmanda), and Jim Brass (Paul Guilfoyle).

TVLine has compiled an assortment of other behind-the-scenes photos from the shoot, which began on July 29. As previously reported, it won’t be a reunion for all of the show’s notable alums, as Elisabeth Shue and George Eads are not set to appear. The finale is scheduled to air on CBS on Sunday, Sept. 27.

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