The researcher, StevenHatfill, 48, had previously been questioned in the investigation of last fall's anthrax attacks and had his apartment searched in June.
Early in the investigation, then-Attorney General John Ashcroft publicly identified former civilian anthrax researcher StevenHatfill as a "person of interest" in the investigation.
Wednesday's announcement comes six years to the day after then-Attorney General John Ashcroft publicly declared another Fort Detrick scientist, StevenHatfill, a "person of interest" in the attacks.