Lawmakers Seek Anthrax Details A month after the F.B.I. declared that an Army scientist was the anthrax killer, leading members of Congress are demanding more information about the seven-year investigation, saying they do not think the bureau has proved its case. In a letter sent Friday to Robert S. Mueller III, the director of the Federal Bureau of Investigation, Democratic leaders of the House Judiciary Committee said that “important and lingering questions remain that are crucial for you to address, especially since there will never be a trial to examine the facts of the case.” The scientist, Bruce E. Ivins, committed suicide in July, and Mr. Mueller is likely to face demands for additional answers about the anthrax case when he appears before the House and Senate Judiciary Committees on Sept. 16 and 17. “My conclusion at this point is that it’s very much an open matter,” Senator Arlen Specter of Pennsylvania, the top Republican on the Senate committee, said of the strength of the case against Dr. Ivins, a microbiologist at the Army’s biodefense laboratory who worked on anthrax vaccines. “There are some very serious questions that have yet to be answered and need to be made public.”....