Ana Bruni, was suspended on Friday for allegedly using an office computer to obtain the names of grand jury witnesses, a Justice Department official told The Detroit News.
Bruni allegedly passed on the information to the main target of the grand jury's investigation, Richard G. Convertino, the lead prosecutor in the 2003 Detroit trial.
A special federal grand jury is nearing the end of its investigation into whether three government officials conspired to obstruct justice and suborn perjury in the first terror case to go to trial after the investigation into the Sept. 11, 2001.
Convertino, FBI Special Agent Michael Thomas and another witness at the trial are under investigation.
Convertino won a 2003 conviction claiming four Arab immigrants were part of a sleeper cell plotting violent attacks in the Middle East and Michigan.
The convictions were tossed out in 2004 by U.S. District Judge Gerald E. Rosen after a Justice Department review found prosecutors suppressed evidence that might have bolstered the defendants' claims of innocence.