Hatfill collected parts for the mockup and supervised its construction at a metal shop in Frederick, Md. in September 2001, just before letters containing deadly anthrax spores were mailed to Congress and several other locations. Five people died in the anthrax attacks.
Months prior to the Iraqi invasion, U.S. special forces troops trained on Hatfill's mockup to learn how to detect and disarm a germ lab, should they encounter one in the war.
Law enforcement officials said, however, that the mockup was "never made operational," that "no anthrax spores" were ever found on the equipment, and that there is "no evidence thus far" linking Hatfill and the mockup to the anthrax attacks.
Construction of the lab and Hatfill's involvement were first reported by The New York Times, which said that even after the FBI began looking at Hatfill as a possible suspect, the Pentagon continued to "draw on [Hatfill's] expertise" as a germ warfare expert.
The FBI's disclosure comes just days after another disappointment for investigators, who recently drained a suburban Maryland pond hoping to find evidence linking Hatfill to the attacks. So far tests have revealed nothing helpful.
Friends of the scientist, meanwhile, continue to maintain his innocence.
"I haven't seen any evidence that he's done anything wrong on his resumes, in his work for the government, in the military. I'm still waiting to see some proof," said Pat Clawson.
And the FBI is still waiting for some hard evidence. So far most of what they have is a string of coincidences and leads.
Much like the Iraqi mockup, they look promising at first, but never quite pan out.