WASHINGTON -- The bioterrorism expert under scrutiny in the 2001 anthrax attacks filed a lawsuit Tuesday accusing Attorney General John Ashcroft and other government officials of trampling his constitutional rights and using him as a scapegoat for their failure to make an arrest in the case. Dr. Steven J. Hatfill claims that, by labeling him a "person of interest" in the case, Ashcroft and other federal authorities have destroyed his reputation and ruined his job prospects.