Earlier this year it was learned that Baxter International Inc., which has developed a flu vaccine, was responsible for releasing live flu viruses. From the Toronton Sun:
The company that released contaminated flu virus material from a plant in Austria confirmed Friday that the experimental product contained live H5N1 avian flu viruses. ...Was this a simple mistake?
... The contaminated product, a mix of H3N2 seasonal flu viruses and unlabelled H5N1 viruses, was supplied to an Austrian research company. The Austrian firm, Avir Green Hills Biotechnology, then sent portions of it to sub-contractors in the Czech Republic, Slovenia and Germany.
Then came the story of vials containing a "potentially lethal pathogen" that went missing from a U.S. military lab in Fort Detrick, Maryland. This is the same lab, by the way, to which the deadly 2001 anthrax mailings were traced.
Without drawing any conclusions here, one can certainly see how rumors and conspiracy theories get started.