Handling of anthrax inquiry faulted

The National Research Council committee held a briefing on its 170-page report, which examines the novel microbial forensic techniques used by the FBI to conclude that Bruce Ivins acted alone in making and sending the powdered spores.

The panel faulted government assertions that the mailer must have had a high level of technical skill and that the parent material of the anthrax strain used in the attacks had to have come from a flask that Ivins alone maintained.

“We find the scientific evidence to be consistent with their conclusions but not as definitive as stated,’’ said Alice P. Gast, the president of Lehigh University, who chaired the 16-member panel.

The FBI said in a written statement that its conclusions were based on a traditional investigation as well as scientific findings. The agency said science provides leads but alone rarely solves cases.

“The FBI has long maintained that while science played a significant role, it was the totality of the investigative process that determined the outcome of the anthrax case,’’ the agency said.

Gast declined to comment on the guilt or innocence of Ivins, who died of an apparently intentional Tylenol overdose in 2008 as the US Justice Department prepared to indict him for the attacks. He had denied involvement, and his lawyer and some colleagues have maintained he was an innocent man hounded to self-destruction.

Early last year, the FBI formally closed its investigation into the anthrax letters that unnerved a nation still reeling from the Sept. 11, 2001, attacks, saying it had concluded that Ivins planned and executed the mailings by himself.

Five people died in October and November 2001 from anthrax inhalation or exposure linked to the letters. They were a Florida photo editor, two postal workers in Washington, a hospital employee in New York City, and a 94-year-old woman in Oxford, Conn. Seventeen others were sickened.

Postal facilities, US Capitol buildings, and private offices were shut for inspection and cleaned by workers in hazardous materials suits from Florida to New York and elsewhere.

Investigators have acknowledged that the case against Ivins, who worked at Fort Detrick in Frederick, is circumstantial. Still, Jeff Taylor, the US attorney for the District of Columbia, said in 2008 that prosecutors could prove to a jury beyond a reasonable doubt that Ivins was responsible for the attacks.

The FBI asked the congressionally chartered council to validate its use of new and emerging science in the investigation.

The panel said the science didn’t support the Justice Department’s statement in a 2010 report that “the anthrax mailer must have possessed significant technical skill,’’ an assertion that narrowed who could have been responsible.

The committee said the methods used should be reviewed.