In July 2016, Comey made the controversial decision in July 2016 to announce that he was recommending that no charges be filed over the investigation into her emails. Then, days before the election, Comey announced new emails had surfaced in the case. Clinton herself has blamed Comey in part for her election loss to Mr. Trump.
President Trump fired Comey in May 2017, initially pointing to the justification by Deputy Attorney General Rod Rosenstein that Comey had badly mishandled the conclusion of the Clinton investigation, calling it a "textbook example of what federal prosecutors and agents are taught not to do."
DOJ Inspector General Michael Horowitz launched the review in January of 2017, the same month Mr. Trump took office.
CBS News' Kathryn Watson contributed to this report.
