An Islamic group based in New York said that a recent episode of “South Park,” the satirical animated series, insulted the Prophet Muhammad, and compared the show’s creators, Trey Parker and Matt Stone, to Theo van Gogh, the Dutch filmmaker who was killed in 2004 by an Islamic militant, CNN reported. The group, Revolution Muslim, published its post after a “South Park” episode last week that depicted the founders of various religions, including Moses, Jesus and Buddha, but declined to show the Prophet Muhammad, instead representing him as wearing a bear costume. The post, written by Abu Talhah Al-Amrikee, said that the episode had “outright insulted” Muhammad, adding: “We have to warn Matt and Trey that what they are doing is stupid, and they will probably wind up like Theo van Gogh for airing this show. This is not a threat, but a warning of the reality of what will likely happen to them.” Mr. van Gogh was killed in Amsterdam after making a film that discussed the abuse of Muslim women in some Islamic societies. A telephone message left at a number listed on the group’s Web site, revolutionmuslim.com, was not immediately returned; on Wednesday the Web site was largely inaccessible. Comedy Central declined to comment on the group’s remarks or say if it was taking any precautions because of them.