She was a very private person, not much of a talker about her life and detailed habits from what I've gathered via FR, tv, Time and Newsweek Mags.
If so, it could probably have been someone she knew or one that knew her that infected her. She could have been chosen specifically because of the above and the perp knew of her habits. He'd be less likely to be caught and there'd be no family publically, on tv, pushing the cops to find out what happened, how she got it.
Someone connected to her work place? It would have a lab..but since I don't know much about the manufacture of a more weaponized anthrax, eg. smaller particles, I don't know if the lab would have all or most of what is needed to manufacture the anthax.
Would it have been political or personal? The only private smallish company affected was the hosital that the lady worked for. The rest were huge businesses and a demonrat's office/mail.
OR for some reason her mail had ALOT of contamination/cross contamination with the last batch of anthrax but they've ruled that out, haven't they? No anthrax on her clothes or in her house, mailbox, where she worked.
Just because the anthrax can be treated is no sign it is not dangerous. It is still deadly to anyone who does not EXPECT to be a target and therefore does not go to a doctor at all or waits until it is too late.
And the perp only has to infect one unexpected place, like a grocery store in LA or Houston. One store... and it could cause a HUGE panic. Because you won't what the next place will be. The anthrax threat is STILL alive and well.