Saw IV is a 2007 American horror film directed by Darren Lynn Bousman from a screenplay by Patrick Melton and Marcus Dunstan, and a story by Melton, Dunstan, and Thomas Fenton. A sequel to Saw III (2006) and the fourth installment in the Saw film series, it stars Tobin Bell, Scott Patterson, Costas Mandylor, Betsy Russell, and Lyriq Bent.

Plot

An autopsy of the Jigsaw Killer reveals a wax-coated microcassette in his stomach. Detective Mark Hoffman is called in to listen to it. The tape promises him that "the games have just begun." In a mausoleum, a man named Trevor and lawyer Art Blank are chained to a large device. Trevor's eyes and Art's mouth have been sewn shut, making communication between them impossible. When the device begins pulling them together, they panic, and Art eventually kills Trevor to retrieve a key from his collar.