LOS ANGELES — Evidence linking anthrax that killed five people in a series of 2001 letters to a flask of the spores in the laboratory of federal scientist Bruce Ivins was “not as definitive as stated” by the FBI, researchers said Tuesday.
Although the panel gathered by the National Research Council said it had no reason to believe that Ivins was not 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 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 sending out the letters. He had denied involvement in the attacks, and his lawyers continued to deny that he played any role in mailing the letters.
Five people died in the mailings: two postal workers in Washington, D.C.; a hospital employee in New York; a Florida photo editor; and a 94-year- old woman in Oxford, Conn. Seventeen others were sickened, and postal facilities, the U.S. Capitol building 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 Fort Det rick, Md., and that the perpetrator required a high degree of skill, such as that possessed by Ivins, to prepare the powder for mailing and dispersal.
The NRC report, “Review of the Scientific Approaches Used During the FBI’s Investigation of the Anthrax Letters,” agreed that the anthrax in Ivins’ lab was the dominant strain in the letters but noted that there were genetic differences in the materials in the New York and Washington letters, suggesting it had been cultured elsewhere before being mailed.
The committee noted that silicon was present in the samples but 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 panel also concluded that a high degree of technical skill was not required to prepare the samples that were used in the letters and that they were, in fact, a relatively crude preparation.
