I agree. The nature of the stuff is that only a handful of people knew how to make, and transmit this, efficiently. That's why Hatfill is such a suspect. He was involved in all sorts of training ops in the 1990s. It may only be that he showed someone how to do it who later turned out to be a terrorist, but it's suspicious.
We can draw one strong suspicion from all evidence collected so far and the events that occurred. If Hatfield didn't committ the act...the person who did committ the act...knew Hatfield to a great extent. There were more than just one or two cards drawn on the table to lead at Hatfield in a strong manner...so the offending party had know certain portions of his history (not the current stuff...but over 20 years of his history). When you see no repeat of anthrax affair...no further attempts...this leads to a person who had an agenda to worry people in a certain direction. The guy who did this...wanted a massive government support program and knew he or she was in the position to be a major player in that anthrax program.