You folks seem to be forgetting that the media was attacked by terrorists. NBC, CBS, and ABC each received letters containing deadly forms of anthrax in 2001, starting about seven days after 9/11. The letter sent to NBC was addressed specifically to Tom Brokaw. A number of Democratic congressmen also received letters containing anthrax at the same time. Twenty-three people contracted the disease, and five people died.
The letters refer to Sept. 11th and also say "Allah is Great!", suggesting that al-Qaeda is behind the attack. However, letter attacks do not appear to be al-Qaeda's style.
The FBI is implicating a lone wacko (surprise, surprise!), but it's hard to imagine that a single person would have access to the kind of materials required to produce this type of anthrax. Furthermore, the anthrax inside the letters has been traced to a strain cultivated in US military laboratories.