Hardly
A vial of Clostridium Botulinum is NOT a smoking gun. Its a naturally occurring bacterium you could readily cultivate yourself. It is not even a biological weapon. It can be used to produce botulinum toxin. But if you haven't found viles of the toxin, you haven't found evidence of a bio-weapons program. Fact is, Clostridium botulinum is readily used here in the United States in the manufacture of the commercial product Botox.
I see we are still tilting at windmills here.