WASHINGTON — Despite the Justice Department's pronouncement that former Army microbiologist Bruce Ivins unleashed the 2001 anthrax attacks that killed five people, three central questions about the case remain unanswered:
_ Can the FBI prove that a flask of anthrax in Ivins' bioweapons laboratory at Ft. Detrick, Md., contained the same mutated strain of finely milled powder that was in the envelopes that were mailed to two U.S. senators?
_ Did Ivins, who committed suicide last week, have the technical capability to produce that form of anthrax?
_ Why, after he came under suspicion in 2005 or earlier, was Ivins allowed to retain a high-level security clearance that enabled him to continue working in the bioweapons laboratory at Ft. Detrick, apparently until this summer?
As federal prosecutors and FBI agents moved to close the seven-year investigation, former employees at the U.S. Army Medical Research Institute of Infectious Diseases and other biological weapons experts Thursday expressed skepticism about the case that's been presented publicly.
The FBI said Wednesday that it had winnowed eight samples that contained all four of the genetic mutations in the anthrax-laced letters out of 1,000 anthrax samples from 16 laboratories and traced all eight to a batch in Ivins' lab that had the same "DNA fingerprint."
However, Jeffrey Adamovicz, who directed the bacteriology division at Ft. Detrick in 2003 and 2004, said the FBI trail is "a little disturbing" because it relies on a common contaminant in laboratories and in the environment.
While the FBI said it found a unique mutation of that contaminant, Adamovicz said, it has yet to say that this strain "was found in Dr. Ivins' lab and no one else's."
Further, he said, that strain of the anthrax organism "has to have a parent somewhere, which means their assertion that it was only in Ivins' lab doesn't make sense."
Donald Henderson, a scholar at the University of Pittsburgh's Center for Biosecurity who assisted the government in dealing with the attacks, said the FBI's case against Ivins "just doesn't add up." He said the FBI must produce its DNA evidence for scrutiny by scientists.
Some of Ivins' former colleagues also dispute the FBI's assertion that he had the capability to mill tiny anthrax spores and then bind them to silicon particles, the form of anthrax that was mailed to the office of then-senator Tom Daschle, D-S.D..
Adamovicz said the anthrax sent to Daschle was "so concentrated and so consistent and so clean that I would assert that Bruce could not have done that part."
"Just because you're off your rocker doesn't mean you can make something that no one else in the world can make with the kind of equipment that's available," said Richard Spertzel, who worked in the lab for 21 years before he retired in 1987.
Spertzel called the FBI's focus on records that Ivins had checked out a device that could freeze-dry tiny anthrax spores "a red herring," and said he doubted that the lab possessed the equipment needed to mill the spores.
Another mystery is why Ivins wasn't escorted from the facility until last month when the FBI had discovered by 2005 that he'd failed to turn over samples of all the anthrax in his lab, as agents had requested three years earlier.
Caree Vander-Linden, a spokeswoman for the institute, said that lab supervisors monitor their scientists' behavior and that, under a Biosurety Program that was implemented in 2003, all researchers undergo intrusive background checks.
Adamovicz said that under that program, scientists are required to disclose any mental health issues. Scientists also must undergo periodic FBI background checks to retain their security clearances.
Adamovicz said that Ft. Detrick officials knew by late 2006 that Ivins was a suspect, yet he retained his laboratory badge for nearly a year after that. His badge was withheld on Nov. 1, 2007, the day the FBI searched his home, but it apparently was reinstated.
"It's hard to understand if there was all this negative information out there on Bruce, why wasn't it picked up in the Biosurety Program or by law enforcement," Adamovicz said.
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