Here is one of a bunch of cases where a fed attorney, who was not authorized to be a prosecutor but worked on a prosecution caused the case to be vacated. How the hell can the DOJ say they do not have certifications of authority for their prosecutors. Look at just one of them here: US v Forman (1995); Although the attorney in question was a federal attorney assigned to the SEC, because they were not specifically authorized to act as an AUSA, the case had to be vacated.