New evidence in Ivins anthrax case raises questions

Lab data buried in the FBI’s report of the 2001 anthrax attacks suggests that chemicals may have been added to increase the potency of the anthrax powder that was used, a technique that some experts believe may have been too sophisticated for the presumed killer.

Two of the five letters sent by the perpetrator contained unusual levels of both tin and silicon, a fact included in nearly 9,000 pages of files that emerged after the Justice Department closed its inquiry and pointed to Bruce Ivins as the perpetrator of the attacks, according to

Both elements are found in compounds that could have been used to weaponize the anthrax powder, creating conditions where the spores could float easily into the lungs of its victims.

The silicon-tin chemical signature gave investigators the possibility to track purchases of such chemical products before the attacks, which could have led them to hard evidence against Ivins or a different culprit, reports. The recently released FBI lab reports gave no indication that agents had attempted to track the purchasers of additives like tin-catalyzed silicon polymers.

A senior law enforcement official speaking under the condition of anonymity said that the FBI concluded, after exhaustive testing, that silicon was not added and that its existence was part of a natural phenomenon by which the anthrax added environmental silicon as a coating, according to McClatchy.

The FBI would have had to discount its own tests that showed silicon comprised 10.8 percent of the anthrax powder used in a letter mailed to the New York Post and as much as 1.8 percent of the powder sent to Sen Patrick Leahy (D-Vermont). Tin, which is not usually used in anthrax powder, was also found in both letters in small quantities.

An FBI spokesman declined to comment on the silicon and tin findings, but several scientists argue that Ivins, as a career biologist, probably lacked the chemistry skills needed to create a silicon-based additive, reports.

Martin Hugh-Jones, an anthrax expert who teaches veterinary medicine at Louisiana State University, called it “just bizarre” that the FBI found both tin, which can be toxic to anthrax bacteria, and silicon in samples it tested from the attacks.

Officials from the FBI say the point is irrelevant because they found the culprit in Bruce Ivins, a mentally troubled researcher at the U.S. Army Institute of Infectious Diseases at Fort Detrick, Maryland. Ivins killed himself with an overdose of drugs when he learned that he was the focus of the FBI’s case and could face five counts of capital murder.

The FBI closely guarded its silicon findings at a hearing before the House Judiciary Committee in September 2008, saying that a reliable quantitative measure was not possible for the Post Letter and that silicon made up 1.4 percent of the Leahy powder.

Since the investigation began, several laboratories, including the Sandia National Laboratories, the Armed Forces Institute and Lawrence Livermore National Laboratory, have analyzed the FBI’s findings or the natural rate of silicon absorption by anthrax, but have yet to settle the issue.

"It'd be really helpful for closure of this case if that was resolved," Peter Weber, a co-researcher for Lawrence Livermore National Laboratory study commissioned by the Department of Homeland Security, said, according to