According to its website, the FBI has "devoted hundreds of thousands of agent-hours to the case," conducted more than 9,100 interviews, obtained about 6,000 grand jury subpoenas and completed 67 searches.
A federal judge who reviewed details of the anthrax investigation, including still-secret FBI summaries, declared earlier this year: "There is not a scintilla of evidence that would indicate that Dr. Hatfill had anything to do with this."
FBI leaders had remained fixated on Hatfill into late 2006, agents said.
"They exhausted a tremendous amount of time and energy on him," said one of the FBI agents involved with the case who spoke to The Times on condition of anonymity because the investigation is continuing.
"I'm still convinced that whatever seemed interesting or worth pursuing was just basically nullified in the months or year following when 'person of interest' came out about Hatfill," he said. Other possibilities got short shrift, he said, because of assumptions within the FBI that "sooner or later they'll have this guy nailed."
Said another investigator: "Particular management people felt, 'He is the right guy. If we only put this amount of energy into him, we'll get to the end of the rainbow.' Did it take energy away? It had to have. Because you can't pull up another hundred agents and say, 'You go work these leads [that] these guys can't because they're just focused on Hatfill.' "
Mueller testified in a deposition that the probe posed tall obstacles. With no obvious suspect initially, he said, the FBI had to conduct "preliminary initial investigations" of a "universe of individuals" with access to the strain of anthrax used in the attacks. He said he had told aides "to take what steps were necessary to prevent leaks," which he believed had "undercut" the investigation.
An FBI spokesman, Michael P. Kortan, said Mueller would not comment for this article. The spokesman added that "solving this case is a top priority for the FBI. Our commitment is undiminished."
A plume of powder
On Oct. 15., 2001, Mueller assigned the anthrax investigation to Van Harp, a 32-year veteran of the FBI. That morning, an aide to the U.S. Senate majority leader, Thomas Daschle (D-S.D.), opened an envelope on Capitol Hill, releasing a plume of powdery material. A photo editor in Florida had died mysteriously from anthrax 10 days earlier.
