In the circumstantial case against Dr. Bruce Ivins, what's missing is direct and forensic evidence which would tie Ivins to the anthrax letters. He fooled handwriting analysts by "disguising his handwriting", the FBI says. Ivins passed two lie detector tests, but the results of those examinations were not included in the evidence. Instead, the search warrants seek to find in Dr. Ivins's home materials relating to "how to defeat a polygraph".

Newsweek reports, quoting Justice Department official Dean Boyd:

"He was told he passed [the polygraph] because we thought he did," said Justice official Boyd. But after the FBI learned of Ivins's history of psychological problems, it had its experts re-examine the results, and they concluded he'd used "countermeasures" such as controlled breathing to fool the examiners.

What the FBI doesn't explain is why a man who is so clever and sinister that he can fool both handwriting analysts and polygraph examiners would leave a paper trail that could incriminate him as being the anthrax killer.

The FBI leaked a claim that Dr. Ivins took a leave of absense from the Ft. Detrick lab during the crucial "window of opportunity" for mailing one of the anthrax letters. The Washington Post reported:

A partial log of Ivins's work hours shows that he worked late in the lab on the evening of Sunday, Sept. 16, signing out at 9:52 p.m. after two hours and 15 minutes. The next morning, the sources said, he showed up as usual but stayed only briefly before taking leave hours. Authorities assume that he drove to Princeton immediately after that, dropping the letters in a mailbox on a well-traveled street across from the university campus. Ivins would have had to have left quickly to return for an appointment in the early evening, about 4 or 5 p.m.

The problem with this accusation is that if those letters were put in the mailbox before 5 p. m., when Ivins was already back in Frederick, the letters would have been postmarked September 17. The letters with anthrax, however, were postmarked on September 18.

Confronted with the obvious blunder, FBI officials then changed their theory to adapt to the facts. In a story entitled, "Hair Samples in Anthrax Case Don't Match", the new theory was offered:

>>>Investigators now believe that Ivins waited until evening to make the drive to Princeton on Sept. 17, 2001. He showed up at work that day and stayed briefly, then took several hours of administrative leave from the lab, according to partial work logs. Based on information from receipts and interviews, authorities say Ivins filled up his car's gas tank, attended a meeting outside of the office in the late afternoon, and returned to the lab for a few minutes that evening before moving off the radar screen and presumably driving overnight to Princeton. The letters were postmarked Sept. 18.

None of these inconsistencies should matter, the FBI tells us, because state-of-the-art DNA testing had provided a "genetic fingerprint" that led them to a flask of anthrax created and controlled solely by Dr. Ivins. From the FBI's press conference:
 

First, we were able to identify in early 2005 the genetically unique parent material of the anthrax spores used in the mailings. As the court documents allege, the parent material of the anthrax spores used in the attacks was a single flask of spores, known as "RMR-1029," that was created and solely maintained by Dr. Ivins at USAMRIID. This means that the spores used in the attacks were taken from that specific flask, regrown, purified, dried and loaded into the letters. No one received material from that flask without going through Dr. Ivins.

The Baltimore Sun later reported:
 

The government said that 16 government, commercial and university labs had the strain of anthrax with the same genetic mutations as the anthrax used in the attacks. Only one of those 16 was in Maryland or Virginia - where the government thinks the envelopes used in the attacks were purchased. That lab is the one where Ivins worked. ...

... And even at Fort Detrick, the government said that more than 100 people had access to the flask, creating a lot of room for reasonable doubt.

Members of the scientific community remain skeptical. They would like to see the data behind which the FBI makes the claim that Dr. Ivins was the sole possessor of the anthrax used in the attacks but the FBI, thus far, has not released the scientific data.

Gerry Andrews, assistant professor of microbiology at the University of Wyoming, writes:

As a scientist, however, I feel compelled to comment on what should have been the Federal Bureau of Investigation’s strongest link between Dr. Ivins and the terrible crime — deadly anthrax spores. In the summary of its findings, the F.B.I. states that investigators used four different genetic techniques to match the anthrax-laced attack letters to a unique DNA footprint of a single anthrax spore preparation in one flask that had been in Dr. Ivins’s custody.

Sounds reasonable. Yet the investigators present no details on the scientific methods they used to make this match or how they employed them. That’s a problem, because without such detail it is hard to tell if they specifically ruled out a similar match between the anthrax in the letters and anthrax preparations with the same DNA footprint kept at a number of other labs around the country. The basic methods of genetic analysis are well known. Why not provide enough detail about their procedure to enable other scientists to tell whether they could actually single out Dr. Ivins’s spore preparation as the culprit?

From McClatchy Newspapers:

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.

From the Washington Post:

"There is not enough scientific information to make an evaluation of the science the FBI used in this investigation," said Tara O'Toole, who heads the Center for Biosecurity at the University of Pittsburgh.

Will the FBI release the scientific data to back up its claims?

Congress will reconvene after Labor Day, and the Senate Judiciary Committee has scheduled a hearing with FBI director Rober Mueller for September 17. Republican Senator Chuck Grassley, who sits on this committee, has laid out 18 questions he would like the answers to.