I have a bit of a brain-dead acquaintance (in California, of course) who is denying that US DOD bio-weapons labs ever existed and says it's all Russian propaganda. I have provided four different sources to back me up, but all I get back is "not proof" and "I don't believe it."

Does anyone have a best source (not the Russian claims, I've already provided that) that report convincingly and reliably that these labs did exist?

Thanks, anons.