[Sabertooth]

What if one bad guy on antibiotics, mailed an anthrax envelope to another bad guy on antibiotics, or even to himself. As long as the envelope wasn't lumpy or scattering visible dust, it would secretly contaminate the postal system en route and then conveniently disappear.

Plausible, even more than you think, from a medical standpoint... The guys could be vaccinated.

But they'd have to be mighty dumb to put their own address on an anthrax letter, on the chance it might get detected before getting back to them.

[mfulstone]

Simple scenario- Mail the letter to a fake address. It goes thru the mail and winds up in the dead(ly) letter office or whatever they do with them these days.

[Neuromancer]

Much more likely scenario: Bad guys drop anthrax laden letter into box with a phony address and a phony return address. Pin holes in the corners or such would allow for the dispersal of the spores.

The letter(s) then go to the fake address - are returned and then sent back to the fake return address. Eventually ending up in a dead letter file in some Post Office. Very effect delivery system - hard to trace back.

These are bright and evil perps. Hope we get them soon...