SCIENCE -- February 15, 2011 at 5:41 PM ET
Science Alone Won't Close the Case on Anthrax, Committee Says
In September 2001, letters containing anthrax were mailed to two senators and several news media outlets. Five people died and at at least 17 fell ill. Fear of anthrax gripped a nation already rocked by the 9/11 attacks.
Seven years later, senior Army microbiologist Bruce Ivins, who had spent much of his career working with anthrax, and who had become a top suspect in the ensuing anthrax investigations, swallowed a bottle of Tylenol pills and died in an apparent suicide. Last year, the government ended its investigation into the incidents after concluding that Ivins had prepared and sent the anthrax-laced letters.
On Tuesday, the story took a new twist when a committee convened by the National Academy of Sciences and commissioned by the FBI found that scientific evidence alone is not sufficient to link the flask of anthrax grown in Ivins' lab to the infested letters, casting doubt on that FBI finding.
"The significant link between the letter material and the flask number RMR-1029 is not as conclusive as stated in the DOJ investigative summary," said panel chair and Lehigh University president Alice Gast in a briefing.
Some of the FBI science was solid, the report concludes. The agency correctly identified the strain of bacteria, known as RMR-1029, as B. anthracis. And there was no evidence that silicon "had been added as a dispersant to 'weaponize' the anthrax," committee scientists and the FBI agreed.
But the FBI, the committee said, should have made better use of advanced forensic science technology, such as molecular methods to identify anthrax samples.
"Using tools such as high-throughput, 'next generation' DNA sequencing could have strengthened or weakened the association between spores found in the mailed letters and spores from RMR-1029," said David A. Relman, the committee's vice chair. "Such new technology will be important to similar investigations in the future."
The committee included microbiologists, statisticians, biochemists and public health experts. Panel members combed through nearly 9,600 pages of material and produced their own 190-page document. Their job, Gast said, was not only to review the FBI investigation of the anthrax attacks, but also to ensure that future biological attacks be investigated effectively and with rigor.
A joint statement by the FBI and the Justice Department said that it was the totality of their review, not just the scientific evidence, which led them to conclude that Ivins was responsible for the attacks. Unlike the FBI, the committee did not have access to Ivins' e-mails and conversations, and made no judgment about his guilt or innocence.
"Although there have been great strides in forensic science over the years, rarely does science alone solve an investigation," the FBI/DOJ statement reads. "The scientific findings in this case provided investigators with valuable investigative leads that led to the identification of the late Dr. Bruce Ivins as the perpetrator of the anthrax attacks."
There are two forms of anthrax. In its spore, or inert form, it is passive and doesn't change or mutate. But upon entering a warm or moist environment, it can transform into an active form. Once active, it begins to multiply, releasing toxins during the reproductive process.
Anthrax, when inhaled, is the optimal size to wield injury. Once deep in lungs, it destroys the body from within, shutting down the lungs and infecting the heart and other organs. "After literally three or four days, if you did a microscopic examination of your blood, one-third of the volume would be tiny, vegetative anthrax bacteria," said bioterrorism expert Leonard Cole. "It looks like teeny, squiggly worms."
The FBI, Cole added, would have done better to wait until the NAS committee was done deliberating before closing the case. "It's beyond my comprehension why the FBI would end the investigation before the committee had announced its findings," Cole said. "In the end, it could well be that Ivins was the person who the FBI believed he was. But it seems they've punctured some of their own case by raising these questions unnecessarily."