Has anyone seen any indication of how concentrated the anthrax spores were in the powders tested? I've only heard reports of (a few) spores being detected. It occurs to me that it would take much less sophistication to produce a powder with just a few spores - enough to be detectable and to cause a few infections - than it would to produce a really deadly weapon. Anthrax is, after all, found in the soils of many US states and other areas.

On the other hand, the panic, the fear, and the drain on resources caused by low grade powders being sent around would be a very high payoff. The means to produce such low grade powder would be avaialble to a wider range of terrorists. For something that has "only" killed one person (one too many of course) this campaign has extracted a very high cost already.

I hope the FBI and other investigators are looking at all possible sources, and not just bin Laden et al. It would be an ideal time for someone else to capitalize on the situation. (I think it probably is connected to bin Laden, but all sources have to be considered).