An estimated 200 U.S. scientists dealt with the anthrax program over the last five years and federal authorities have told ABCNEWS they are now investigating the activities of a senior research scientist who was twice fired from Battelle and allegedly made a threat to use anthrax in the days after Sept. 11.As Joe Lockjaw would say, "this is old news." Time to "move on."According to an FBI affidavit, agents searched the home of one former top Battelle scientist in late September after he allegedly made threats about using anthrax. Agents said they found suspicious chemicals but no anthrax, according to the sources.