Whatever the source, the material (especially that sent to Capitol Hill) was so finely milled a state was certainly involved. And if anyone doesn't think it was meant as another warning, he's nuts.
I agree. I think this is one of the reasons that Bush invaded Iraq. The Taliban did not have the ability to manufacture "weaponized" anthrax. By process of elimination it came from Iraq ( motive, method, capability spelled oil money, and method). For the Iraqi's, the anthrax was just a "prank" and an experiment to see if it could be effective in the US. To the "war room" in the WH, it was gut evidence that Iraq was associated with 9/11. Bush did his duty as CIC.