Evidence linking the anthrax that killed five people in 2001 to a flask of spores in the laboratory of federal microbiologist Bruce E. Ivins was not as definitive as the FBI claimed, a panel of researchers said Tuesday.
Although the panel assembled by the National Academy of Sciences did not dispute that Ivins was the perpetrator of the terrorist act, it faulted the FBI’s conclusions that the perpetrator must have had a high level of skill to produce the powdered spores and that the spores must have come from Ivins’ lab.
“We find the scientific evidence to be consistent with their [the FBI’s] conclusions, but not as definitive as stated,” panel Chairman Alice P. Gast, president of Lehigh University, said at a news conference.
Ivins died of what appeared to be an intentional overdose of Tylenol in 2008 as the government prepared to indict him for mailing a series of letters containing lethal anthrax spores to two senators and various news organizations.
He had denied involvement in the attacks to the end, and his lawyers continued to deny that he played any role in the act.
Paul F. Kemp, a Maryland lawyer who represented Ivins, said the findings seriously question the FBI’s link between anthrax found in Ivins’ lab and the letters.
The “report turns the FBI’s ‘smoking gun,’ which they bragged so much about, into smoke and mirrors,” Kemp said. “There simply is no evidence to demonstrate that they have any proof of wrongdoing by Dr. Ivins, only their conjecture and conclusions.”
The FBI, however, said in a statement that its conclusions about Ivins’ guilt were not solely based on the scientific evidence, but on “the totality of the investigative process,” including traditional investigative techniques.
The five people who died in the mailings were two postal workers in Washington, D.C., a hospital employee in New York, a photo editor in Florida and a 94-year-old woman in Oxford, Conn. Seventeen others were sickened. Postal facilities, the Capitol and some office buildings had to be shut down to clear them of the deadly substance.
The FBI concluded that the anthrax spores originated in a flask labeled RMR-1029 in Ivins’ laboratory at Ft. Detrick, Md., the Army’s center for biodefense research. The perpetrator required a high degree of skill, such as that possessed by Ivins, to prepare the powder for mailing and dispersal, the FBI said.
The panel’s report, which followed an 18-month investigation, agrees that the anthrax in Ivins’ lab was the dominant strain in the letters but notes that there were genetic differences in the materials in the New York and Washington letters, indicating that it had been cultured elsewhere before being mailed.
The group also suggested that the genetic similarities could be the result of parallel evolution, meaning the spores could have been grown in several laboratories.
The committee noted that silicon was present in the samples but concluded that there was no evidence it had been added to the spores in an attempt to weaponize them — that is, to make them disperse more readily.
The scientists concluded that they could not say with any confidence what level of technical skill was required to prepare the samples that were used in the letters.
Rep. Rush D. Holt, a Democrat from New Jersey, the site of the postal box where the letters were mailed, reintroduced legislation Tuesday to establish an 11-member commission to study the anthrax attacks.
“There are still questions to be answered and still lessons to be learned,” Holt said. “It would take a credulous person to believe the circumstantial evidence that the FBI used to draw its conclusions with such certainty. The FBI has not proven to me that this is an open-and-shut case.”
Sen. Charles E. Grassley of Iowa, the senior Republican on the Senate Judiciary Committee, also called for further investigation of the anthrax scare, saying the new report “shows that the science is not necessarily a slam dunk.”
Maugh reported from Los Angeles and Serrano from Washington.