I have a friend who was very involved in bio warfare at high levels he has long maintained it probably came from Iraq. Also the way it was dispersed (particles were made to float) is a key bit of evidence ....he says it could only have been done in a well equiped lab.
Which any fully competent biotech fella could have in their garage. It is not unknown in these parts for biotech research gurus to personally own all the gear required to genetically engineer biowarfare agents in a weaponized form. The equipment costs some bucks but isn't that expensive, and is generally readily available. A lot of the biotech equipment made in Russia is particularly cheap and quite serviceable.
What has saved us to date is that it takes more brains than money currently to put something nasty together. And that won't last forever.