Science review casts doubt on 2001 anthrax case
WASHINGTON — A scientific review released Tuesday in the 2001 case of deadly anthrax mailings cast doubt on the US government's conclusion that scientist Bruce Ivins, who killed himself in 2008, was to blame.
There was insufficient scientific evidence to support the FBI's assertion that the anthrax in letters sent to prominent politicians and journalists in the wake of the September 11 attacks originated within Ivins' lab, it said.
"It is not possible to reach a definitive conclusion about the origins of the B. anthracis in the mailings based on the available scientific evidence alone," said the report by the National Academy of Sciences.
The anthrax mailings, which killed five people and injured 17, rattled an already jittery American public just days after Al-Qaeda militants hijacked passenger jets and plunged them into the World Trade Center, the Pentagon and a Pennsylvania field.
The review found that anthrax contained in a flask, known as RMR-1029, in Ivins' lab shared genetic similarities with spores in the mailed letters but "was not the immediate source of spores used in the letters."
"One or more derivative growth steps would have been required to produce the anthrax in the attack letters," the report said, adding that the letters sent to Washington had different characteristics than those sent to New York.
"They have enough physical and chemical differences between the two that they must have come from separate batches," said lead author of the report Alice Gast.
"The difference between those letters and the flask indicate there had to be an additional growth step to create letters with the additional characteristics that they found," she told reporters.
The FBI concluded that the mailed anthrax must have come from a single flask of parent spores that Ivins had created and which he alone had maintained.
The type of anthrax contained in the letters, mailed to NBC anchor Tom Brokaw, the New York Post and senators Tom Daschle and Patrick Leahy, was correctly identified as the Ames strain of B. anthracis, which originated from a cow in Texas in 1981 and was shared with labs worldwide, the report said.
But a key problem arose from the way the FBI attempted to narrow down the source of the anthrax by creating a repository of potential samples provided by the labs that maintain them.
The repository was incomplete, leaving the possibility that other sources could remain unexamined, and also relied on scientists to provide their own samples, allowing for manipulation by potential suspects.
"Standards of custody of evidence would dictate that agents of the FBI should have obtained the samples," the report said.
"The sender could have been the instigator and may not have complied with instructions, as the FBI alleges with respect to Dr. Ivins."
Ivins, a bio-defense researcher at the US Army's Medical Research Institute of Infectious Diseases, committed suicide by taking drugstore medications in July 2008 as FBI agents were about to bring charges against him.
Investigators began focusing on Ivins in 2007 after new forensic scientific methods traced the anthrax back to him.
The NAS report was delayed in November 2010 when the FBI, which had just received the final draft for security review, decided to release more, previously classified information for the panel to consider.
FBI investigators had looked at anthrax evidence from "an undisclosed overseas site at which a terrorist group's anthrax program was allegedly located," the report said.
"The information indicates that there was inconsistent evidence of Ames strain DNA in some of these samples, but no culturable B. anthracis," it said adding that the late-arriving information "deserves a more thorough scientific review."
The NAS reviewers also noted that their analysis of evidence was limited to "the biological, physical, and chemical sciences," and did not consider other traditional forensic science methods used by the Federal Bureau of Investigation.
The FBI, which commissioned the NAS report, highlighted the panel's assertion that a definitive conclusion based on science alone "was not possible" and said a combination of factors led investigators to conclude that Ivins was the source.
"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," it said in a statement.
ABC News - Feb. 15, 2011
By PIERRE THOMAS, JACK CLOHERTY and JASON RYAN
Today, the National Academy of Science raised more questions.
A review panel said that the FBI overstated the scientific evidence that linked the anthrax flask controlled by Dr. Bruce E. Ivins to the anthrax used in the 2001 attack letters. Dr. Ivins, a researcher at Ft. Detrick, MD., was identified by the FBI as the primary suspect in the case. He maintained his innocence until his suicide in 2008.
The cornerstone of the FBI case against Dr. Ivins was that the anthrax in the flask to which he had access -- labeled RMR-1029 -- had a unique make-up that identified it as the parent material for the anthrax in the attack letters. It took years of research for the FBI to conclude that the anthrax in the letters came from Dr. Ivins' flask, and they cited it as "powerful evidence" against him.
The NAS has reviewed the FBI's scientific work on the anthrax, and today, Dr. David A. Relman, the vice chair of the NAS panel, said, "One cannot arrive at a definitive conclusion about the origins of the anthrax."
The review by the NAS concludes that while the anthrax in the letters was "consistent with" the RMR-1029 flask, that flask was not the "immediate source" of the spores used in the letters. The NAS found that one or more growth steps would have been required to produce the spores used in the letters. The NAS found that "the data did not rule out other possible sources" of the anthrax.
In addition, the NAS found that the anthrax used in letters sent to New York locations -- including ABC News, NBC News and the New York Post -- had different physical properties from the anthrax in letters that killed several postal workers and closed down some Senate offices in Washington, D.C.
The FBI says it did not rely on science alone to close in on Dr. Ivins. Investigators said they also used circumstantial evidence, including late-night lab visits by Ivins and e-mail messages describing his psychological turmoil, to identify him as a suspect.
In response to the NAS review, the FBI issued a statement saying, "The committee…concluded that it is not possible to reach a definitive conclusion about the origins of the B. anthracis in the mailings based on the available scientific evidence alone. 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."
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