Claims that an Afghan immigrant was on the verge of unleashing a terrorist attack on New York City on the anniversary of the Sept. 11 are missing a key element: explosives or the chemicals allegedly used to make them, the man's attorney said.FBI agents have yet to find those elements and connect them to Najibullah Zazi, charged with conspiring to use weapons of mass destruction in a plot authorities say was aimed at commuter trains, attorney Arthur Folsom told a federal judge in Denver Friday.