In the wake of Desert Fox, the U.S. assault on Iraq last December,UNSCOM--the special UN commission created to find and destroy Saddam Hussein's weapons of mass destruction--has disintegrated amid charges it was really a spy agency. Scott Ritter, former U.S. Marine and UNSCOM inspector, claims U.S. Intelligence destroyed UNSCOM's credibility when American spies penetrated and compromised the UN arms inspection teams. FRONTLINE investigates Ritter's charges and asks, who really killed UNSCOM?