By Seth Stern, CQ Staff

Members of the House Judiciary Committee made clear Friday they expect more answers from the FBI about its August announcement that a government scientist was responsible for the 2001 anthrax attacks on Capitol Hill and elsewhere.

Committee members submitted a list of questions they want Director Robert S. Mueller III to answer about the anthrax investigation in advance of his first Capitol Hill appearance since the FBI announced Bruce E. Ivins was solely responsible for the attack. Mueller is to appear before the panel Sept. 16.

Ivins, a microbiologist who worked at a U.S. military research institute at Fort Detrick, Md., committed suicide as federal officials prepared to indict him.

“Important and lingering questions remain that are crucial for you to address, especially since there will never be a trail to examine the facts of the case,” wrote Judiciary Chairman John Conyers Jr. , D-Mich., in a letter co-signed by two subcommittee chairmen.

Among the questions they want Mueller to address are whether White House officials initially pressed the FBI to show the attacks were linked to al Qaeda or Iraq and why another government scientist, Steven Hatfill, remained a suspect in the investigation. Judiciary Committee Democrats also want Mueller to explain why Ivins retained his security clearance after becoming the prime suspect in the attacks.

Ivins’ attorney has maintained his client was innocent and lawmakers in both parties have called for an independent investigation.

At least five envelopes containing anthrax spores were mailed to Capitol Hill, New York City and Boca Raton, Fla., in September and October of 2001, shortly after the Sept. 11 terrorist attacks. Five people died as a result. The targets included Senate Majority Leader Tom Daschle, D-S.D. (House 1979-86; Senate 1987-2004), and Senate Judiciary Chairman Patrick J. Leahy , D-Vt.

In addition to the anthrax investigation, the committee also wants Mueller to address the alleged collection of journalists’ phone records, the FBI’s role in investigating problems with the subprime mortgage industry and proposed new guidelines that would direct FBI investigations.

Mueller is scheduled to testify Sept. 17 before the Senate Judiciary Committee.