The long-anticipated Department of Justice Inspector General report critical of fired FBI Director Andrew McCabe is expected to be released Friday afternoon. It claims that McCabe "lacked candor" on multiple occasions in conversations with federal investigators, according to a copy of the report obtained by CBS News.

The inspector general's 39-page report claims that McCabe misled investigators about the FBI's contacts with the media. Specifically, the investigation centered on whether McCabe authorized the disclosure of the contents of a phone call between himself and the then-Principal Associate Deputy Attorney General to Wall Street Journal reporter Devlin Barrett, in what resulted in the article, "FBI in internal feud over Hillary Clinton probe" on Oct. 30, 2016. The article confirmed the existence of the FBI's probe into the Clinton Foundation, separate from its probe into Clinton's use of a private email server.

The investigation lays out that McCabe did indeed authorize the leak in order to counter the narrative that he was attempting to shut down the Clinton Foundation investigation. In total, the report asserts McCabe "lacked candor" on four occasions.

McCabe was fired by Attorney General Jeff Sessions last month, at the recommendation of FBI officials, ahead of the expected report. The inspector general began its work on the report more than a year ago, and the report has long been anticipated in Washington.

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McCabe has called his dismissal part of the "war" on the FBI, and wrote a lengthy op-ed in The Washington Post immediately after his dismissal.

In a Friday statement, McCabe's attorney Michael Bromwich disputed the inspector general's findings, saying that the rush to fire McCabe was "unprecedented, unseemly, and cruel."

"The core weakness of the OIG report is the lack of any understandable motive for his alleged wrongdoing," said the statement in part.

"It is undisputed that Mr. McCabe was one of three senior FBI officials authorized to share information with the media, including on sensitive investigative matters. He chose to exercise that authority in October 2016, during one of the most turbulent periods in the history of the Bureau, with the knowledge of Director Comey and other senior members of FBI management. His purpose was to protect the institutional reputation of the FBI against false claims, including that a sensitive investigation was being shut down for political reasons."

Michael R. Bromwich, McCabe's counsel, said they have long been considering lawsuits.

"We have for some time been actively considering filing civil lawsuits against the president and senior members of the administration that would allege wrongful termination, defamation, constitutional violations and more," Bromwich said. "The distinguished Boies Schiller law firm has recently joined us in this project. This is just the beginning."

The FBI is not commenting on the report, referring questions to the DOJ IG.

Mr. Trump is now lashing out at fired FBI Director James Comey, who is releasing a new book on his time at the FBI. Comey accuses the president of being "untethered to truth," and describes in detail his interactions with Mr. Trump.

Mr. Trump responded to Comey's book for the first time Friday, calling him a "LEAKER & LIAR" and saying he "should be prosecuted."

White House press secretary Sarah Sanders responded to the IG report by saying McCabe and Comey sound like "two peas in a pod."

"I haven't seen the full report but it sounds like two peas in a pod with McCabe and Comey," Sanders said in Friday's press briefing.

Mr. Trump took to Twitter after media outlets published the report, claiming McCabe "LIED! LIED! LIED!"

DOJ just issued the McCabe report - which is a total disaster. He LIED! LIED! LIED! McCabe was totally controlled by Comey - McCabe is Comey!! No collusion, all made up by this den of thieves and lowlifes! — Donald J. Trump (@realDonaldTrump) April 13, 2018

Rep. Trey Gowdy, the Republican chairman of the House Committee on Oversight and Government Reform, said the report confirms the McCabe's firing was "justified."

"Today's Inspector General report confirms FBI Deputy Director McCabe's firing was justified," Gowdy said in a statement. "This report continues to call into question decisions made by FBI leadership in 2016 and 2017, which is why the Oversight and Judiciary Committees will continue our joint investigation into the matter."

CBS News' Rebecca Kaplan, Pat Milton and Kathryn Watson contributed to this report.

This is a developing story and will be updated.