The mailbox just off the campus of Princeton University where the letters were mailed sits about 100 yards away from where the college's Kappa Kappa Gamma chapter stores its rush materials, initiation robes and other property. Sorority members do not live there, and the Kappa chapter at Princeton does not provide a house for the women.

They had even intensively questioned his adopted children, Andrew and Amanda, now both 24, with the authorities telling his son that he might be able to collect the $2.5 million reward for solving the case and buy a sports car, and showing his daughter gruesome photographs of victims of the anthrax letters and telling her, “Your father did this,” according to the account Dr. Ivins gave a close friend.

As the investigation wore on, some colleagues thought the F.B.I.’s methods were increasingly coercive, as the agency tried to turn Army scientists against one another and reinterviewed family members.

One former colleague, Dr. W. Russell Byrne, said the agents pressed Dr. Ivins’s daughter repeatedly to acknowledge that her father was involved in the attacks.

“It was not an interview,” Dr. Byrne said. “It was a frank attempt at intimidation.”

Dr. Byrne said he believed Dr. Ivins was singled out partly because of his personal weaknesses. “They figured he was the weakest link,” Dr. Byrne said. “If they had real evidence on him, why did they not just arrest him?”

Ivins's possession of the drying device, known as a lyopholizer, could help investigators explain how he might have been able to send letters containing deadly anthrax spores to U.S. senators and news organizations.

The device was not commonly used by researchers at the Army's sprawling biodefense complex at Fort Detrick, Md., where Ivins worked as a scientist, employees at the base said. Instead, sources said, Ivins had to go through a formal process to check out the lyopholizer, creating a record on which authorities are now relying. He did at least one project for the Defense Advanced Research Projects Agency that would have given him reason to use the drying equipment, according to a former colleague in his lab.

But that appears to be completely false. Here is the abstract of a 1995 research report, for which Ivins was the lead scientist, reporting on discoveries made as part of their research into anthrax vaccines (h/t substantial). This is the method they described using:

The efficacy of several human anthrax vaccine candidates comprised of different adjuvants together with Bacillus anthracis protective antigen (PA) was evaluated in guinea pigs challenged by an aerosol of virulent B. anthracis spores. The most efficacious vaccines tested were formulated with PA plus monophosphoryl lipid A (MPL) in a squalenel lecithin/Tween 80 emulsion (SLT) and PA plus the saponin QS-21. The PA+MPL in SLT vaccine, which was lyophilized and then reconstituted before use, demonstrated strong protective immunogenicity, even after storage for 2 years at 4°C. The MPL component was required for maximum efficacy of the vaccine. Eliminating lyophilization of the vaccine did not diminish its protective efficacy. No significant alteration in efficacy was observed when PA was dialyzed against different buffers before preparation of vaccine. PA+MPL in SLT proved superior in efficacy to the licensed United States human anthrax vaccine in the guinea pig model.

Clearly, Ivins' legitimate work researching anthrax vaccines entailed the use of a lyopholizer. As the commenter notes, "If you google 'lyophilize' and 'anthrax', most of the pages returned are about anthrax vaccines, which is what Dr. Ivins was working on at Ft. Detrick."

Having watched how [the FBI] collected evidence, I don't have a lot of confidence, and I think the burden is on them to satisfy me, and other members of Congress, that they've done this right. . . . The case seems to me at this point to be circumstantial, and again, without briefings from the FBI, it would be presumptuous of me to say. And it would be presumptuous of people in Central New Jersey to breathe a sigh of relief and say: "They got the murderer. He is no longer at-large." The people deserve better re-assurances than what they've been given.

Let's start with the anthrax in the letters to Sens. Tom Daschle and Patrick Leahy. The spores could not have been produced at the U.S. Army Medical Research Institute of Infectious Diseases, where Ivins worked, without many other people being aware of it. Furthermore, the equipment to make such a product does not exist at the institute [...]

In short, the potential lethality of anthrax in this case far exceeds that of any powdered product found in the now extinct U.S. Biological Warfare Program. In meetings held on the cleanup of the anthrax spores in Washington, the product was described by an official at the Department of Homeland Security as "according to the Russian recipes" -- apparently referring to the use of the weak electric charge [...]

Furthermore, the anthrax in this case, the "Ames strain," is one of the most common strains in the world. Early in the investigations, the FBI said it was similar to strains found in Haiti and Sri Lanka. The strain at the institute was isolated originally from an animal in west Texas and can be found from Texas to Montana following the old cattle trails. Samples of the strain were also supplied to at least eight laboratories including three foreign laboratories. Four French government laboratories reported on studies with the Ames strain, citing the Pasteur Institute in Paris as the source of the strain they used. Organism DNA is not a very reliable way to make a case against a scientist.

The concentrated sample was desalted again using the same buffer, frozen and finally lyophilized using a Speed-Vac. The dried samples were dissolved in 25 μl of the TRIS buffer described above and diluted 1:1 with a 2×SDS solubilization buffer consisting of 50 mM Na 2 CO 3 , 4% (w/v) SDS, 12% (v/v) glycerol, 2% (v/v) 2-mercaptoethanol and 0.01% (w/v) Bromphenol Blue prior to heating at 95° C. for 5 min.