anthrax in aerosol so thoroughly contaminated the Senate Office Building that it had to be closed down for nearly three months. The anthrax also was not pure. It contained a signature of silicon—the anthrax in the New York Post letter was 10 percent silicon when the bulk material was measuredby mass—and also contained traces of tin. The anthrax powder had been packed in standard, pre-stamped, 3 ½-inch-by-6 ¼ inch white envelopes. They were postmarked “Trenton, New Jersey,” and a test of mailboxes in that postal zone indicated that at least one had been sent from Princeton.
The victims provided no further clues. There were five deaths from the inhalation of the anthrax, and seventeen other people were hospitalized. But most appeared to be random exposures caused by anthrax leakage in the postal system.
In the midst of the panic that ensued in the fall of 2001, the government, which had information that it declined to make public, also became uneasy. The CIA had learned that in 1999, al-Qaeda had employed a Malaysian scientist, Yazid Sufaat, to build an anthrax lab near the Kandahar airport in Afghanistan. Had al-Qaeda used anthrax, as the letters themselves suggested? This possibility could not be neglected by the Defense Department, since most of its military personnel had not yet been vaccinated against anthrax. Secretary of Defense Donald Rumsfeld therefore dispatched a top deputy to FBI headquarters to ascertain if the anthrax put U.S. troops at risk. The FBI considered the subject so sensitive at the time that the deputy was not allowed to bring any of his aides to the meeting. He later described the secret briefing as an eye-opener into the FBI’s approach to this biological attack. The FBI assistant director reassured the deputy that it was only a matter of time before they identified the perpetrator. Based on the psychological profile it had already assembled, the view of the FBI task force was that a “lone wolf” American scientist, acting alone, had perpetrated all the attacks. The FBI had narrowed the list down to between 150 and 200 scientists who both had access to lab samples of the Ames strain of anthrax and were located within range of the postal district from which the letters were mailed. The deputy assured the Defense Department executive that all were under surveillance, so there was little dangerof another attack. He expressed confidence that they would quickly determine the guilty party by giving each one of the suspects a polygraph examination. When the Defense Department executive then asked him if the FBI was also investigating and polygraphing foreigners who had access to anthrax (since the Ames strain had been sent to several labs abroad), the FBI assistant director told him that they were focusing on the American scientists, and that he expected that the guilty party would soon reveal himself. That was in 2001.
But the FBI polygraph effort, which went on for another seven years, never produced a culprit. No suspect ever broke. Although the FBI investigation code-named “Amerithrax” consumed “hundreds of thousands of investigator work hours,” making it the most massive inquest in the history of American law enforcement, it produced no further actual evidence identifying the party behind the attack.
The FBI did not find a single witness to the theft, preparation, or mailing of the anthrax. It did not find any of the equipment used to make the powdered anthrax or any growth media that added silicon, tin, or any other of the trace elements found in the envelopes containing the killer anthrax. It did not find anthrax in the homes, automobiles, personal effects, or even garbage of any of the scientists it was investigating. It did not find the original letter from which the photocopies were made, or the photocopy machine on which it was made (although it examined tens of thousands of such devices). On the four letters and envelopes, or tape sealing them closed, it found no