It's always interested me that two of the 9/11 hijackers had what was later determined to be cutaneous anthrax by the physicians and pharmacists who treated them.
Also, the first man to die of anthraax in 10/01 was the boss of the man who rented apartments to the 9/11 hijackers.
I don't believe those kind of coincidences are incidental to the investigation and the FBI has made a major mistake not pursuing the foreign terrorist aspect, imo.