A federal prosecutor in a major terrorism case in Detroit has taken the rare step of suing Attorney General John Ashcroft, alleging the Justice Department interfered with the case, compromised a confidential informant and exaggerated results in the war on terrorism.

Assistant U.S. Attorney Richard Convertino of Detroit accused the Justice Department of "gross mismanagement" of the war on terrorism in a lawsuit filed late Friday in federal court in Washington.

Justice officials said Tuesday they had not seen the suit and had no comment.

The suit is the latest twist in the Bush administration's first major post-Sept. 11 terrorism prosecution, which is now in danger of unraveling over allegations of prosecutorial misconduct.