Since the attacks, a variety of conspiracy theories have been put forward in Web sites, books, and films. Many groups and individuals advocating 9/11 conspiracy theories identify as part of the 9/11 Truth movement. Within six hours of the attack, a suggestion appeared on an Internet chat room suggesting that the collapse of the towers looked like an act of controlled demolition. "If, in a few days, not one official has mentioned anything about the controlled demolition part," the author wrote, "I think we have a REALLY serious problem." The first theories that emerged focused primarily on various perceived anomalies in the publicly available evidence, and proponents later developed more specific theories about an alleged plot. One false allegation that was widely circulated by e-mail and on the Web is that not a single Jew had been killed in the attack and that therefore the attacks must have been the work of the Mossad, not Islamic terrorists.