A long-awaited report by the Justice Department inspector general on the handling of the Hillary Clinton email investigation by the FBI and Justice Department is expected to focus on former FBI chief James Comey and the decisions he made during the course of the Clinton investigation, CBS News' Paula Reid reports.

The findings, which are slated to be released Thursday afternoon, describe Comey as "insubordinate" while also criticizing then-Attorney General Loretta Lynch for weak leadership, Reid also reports.

The IG's report is expected to be over 500 pages.

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Conservative Republicans in particular have been calling for the report to be released, and President Trump has been demanding answers from the DOJ and FBI, tweeting earlier this month, "What is taking so long with the Inspector General's Report on Crooked Hillary and Slippery James Comey. Numerous delays. Hope Report is not being changed and made weaker! There are so many horrible things to tell, the public has the right to know."

What is taking so long with the Inspector General’s Report on Crooked Hillary and Slippery James Comey. Numerous delays. Hope Report is not being changed and made weaker! There are so many horrible things to tell, the public has the right to know. Transparency! — Donald J. Trump (@realDonaldTrump) June 5, 2018

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.