· Even if the perpetrator did not make the anthrax himself, just filling the letters with it was a dangerous operation. The perpetrator therefore must have received the anthrax vaccine recently (it requires a yearly booster shot). The vaccine is in short supply and is not generally accessible, and vaccination records are undoubtedly available. The perpetrator also appears to have special expertise in evading contamination while handling weaponized anthrax.

5. Government Statements, Actions and Chronology
· On 13 Jan. 02 Homeland Security Director Thomas Ridge said "the primary direction of the investigation is turned inward" toward domestic terrorists.

· On 2 Dec. 01 a law enforcement official close to the federal investigation called the concept of a government insider, or someone in contact with an insider, “the most likely hypothesis…it’s definitely reasonable.” Another American official was quoted in the same article saying that, in addition to military laboratories, "there are other government and contractor facilities that do classified work with access to dangerous strains, but it’s highly likely that the material in the anthrax letters came from a person or persons who really had great expertise. We haven’t seen any other artifacts that point us elsewhere."

· Secret or questionable biodefense projects tend to be given to the CIA, DOE or other agencies and contractors instead of to DOD, in order to maintain deniability (for example, only DOD programs have been reported by the US in the annual information exchange about biodefense activities, under the Biological Weapons Convention). Many contractor scientists work in government labs. A CIA spokesman says that CIA scientists work with other government agencies and contractors on the biodefense program.