FBI Discounted Contaminant Clue in Anthrax Case

As the FBI built its case for U.S. Army microbiologist Bruce Ivins being the sole culprit behind the 2001 anthrax mailings, investigators did not pursue a potentially key piece of bacterial evidence that might have pointed them in another direction, McClatchy Newspapers reported on Wednesday (see GSN, March 25).

A close examination by scientists of the anthrax letters that killed five people in 2001 turned up a trace amount of an innocuous bacterial contaminant called bacillus subtilis, whose uniqueness was hoped to serve as a tool in identifying the perpetrator of the biological attacks.

In March 2007, a high-ranking FBI official said the contaminant "may be the most resolving signature found in the evidence to date," according to a now-public memo from the investigation.

The FBI, however, settled on Ivins as its main suspect and only checked for the contaminant in a handful of the work areas used by the many scientists who also worked with the variety of anthrax employed in the attacks. No hint of the contaminant was ever found in any of the hundreds of biological samples taken from Ivins' residence, vehicle, office and laboratory at the Army Medical Research Institute of Infectious Diseases at Fort Detrick, Md.

Ivins committed suicide in July 2008 before facing any charges. The FBI announced in early 2010 that it had wrapped up the anthrax investigation and named the deceased scientist as the sole actor in the attacks. Some lawmakers and former scientific colleagues of Ivins, however, have criticized the investigation and pointed out that no direct evidence was ever found to connect the researcher to the crime (see GSN, April 23, 2010).

"This was not an incidental finding," leading anthrax expert Martin Hugh-Jones said. "The FBI had what I would call an institutional fingerprint. Whoever had that strain of (bacteria) has to answer to the investigators."

Hugh-Jones said he thought Ivins, whom he knew personally, did not have the ability to generate the anthrax powder found in the mailings. He argued that the FBI "dismissed" the criticality of the bacillus subtilis contaminant, which has some physical similarities to anthrax. He allowed, though, that "a bit of housekeeping" might have erased the contaminant's trail in the years before testing on the bacteria finally began.

One federal anthrax investigator who participated in the case told McClatchy that the bacterial fingerprint "didn't pan out." He said authorities examined "thousands" of samples for matches to the contaminant.

In the 12,000 pages of declassified FBI documents on the case, there is little indication of testing conducted on other anthrax scientists' laboratory areas or their caches of the bacillus subtilis material. The federal investigator would not answer how many researchers' work spaces were analyzed.

"They've got thousands of samples, but were they thousands of the right samples?" Hugh-Jones said.

The FBI focused its case against Ivins based on a flask in his possession at the Fort Detrick laboratory that contained anthrax with the same abnormal genetic markers as the spores used in the letters. The bureau ultimately tested more than 1,000 anthrax samples from laboratories around the world for matches to the genetic mutations. The only eight matches to be found all originated from Ivins' flask (see GSN, April 18; Greg Gordon, McClatchy Newspapers/Miami Herald, April 20).

April 21, 2011
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As the FBI built its case for U.S. Army microbiologist Bruce Ivins being the sole culprit behind the 2001 anthrax mailings, investigators did not pursue a potentially key piece of bacterial evidence that might have pointed them in another direction, McClatchy Newspapers reported on Wednesday (see GSN, March 25).