Four and a half years after Columbine, four fictional films are tackling school mayhem. Gus Van Sant's ''Elephant'' (Oct. 24), which won the Palme d'Or at Cannes in May, uses cinema verite techniques to mimic aspects of the April 1999 killings. Meanwhile, the Gene Hackman -- Dustin Hoffman thriller, ''Runaway Jury'' (Oct. 17), based on John Grisham's 1996 novel, briefly refers to a school killing and exchanges the book's central court case involving a cigarette company for a firearms trial. ''Zero Day'' (Sept. 3) depicts two school killers as they plan their mission, and ''Home Room'' (Sept. 5) tracks a kid who's injured in a school shooting and her friendship with a prime suspect. It's a film writer-director Paul F. Ryan hopes can make an impact: ''Home Room'' is an opportunity to start a discussion without anybody in the real world getting hurt.''