The Department of Justice’s internal watchdog has reportedly sent prosecutors the findings of a probe into former deputy FBI director Andrew McCabe, who was fired after being found to have misled investigators.

Referring the information to the US attorney’s office would pave the way to potentially opening a criminal investigation. A spokesman for the US attorney’s office in Washington, DC declined to comment, saying he could not confirm or deny media reports detailing the referral. The Department of Justice declined to comment.

An investigation by Justice Department’s inspector general concluded that Mr McCabe had authorised officials to speak with a Wall Street Journal reporter but then “lacked candour” when he was repeatedly asked about the matter.

“The FBI expects every employee to adhere to the highest standards of honesty, integrity, and accountability”, attorney general Jeff Sessions said in a statement announcing he was terminating Mr McCabe’s employment.

In response to losing his job, Mr McCabe released a lengthy statement saying he had been “singled out” and decrying an an “unrelenting assault” on his reputation and that of the FBI in general as special counsel Robert Mueller’s investigation encircles the White House.

“The President’s tweets have amplified and exacerbated it all”, he said.

As Mr Mueller’s investigation into Russian election interference and potential ties to the Trump campaign has unfolded, Donald Trump and allies have raged against what they describe as the political bias of the Justice Department and the FBI – and Mr McCabe became a prominent target.

Mr Trump repeatedly savaged the former FBI official, suggesting on Twitter that campaign donations to Mr McCabe’s wife from allies of Hillary Clinton compromised Mr McCabe’s role overseeing an investigation into Ms Clinton’s use of a private email server.

The inspector general report draws on that thread, saying Mr McCabe channelled information to the media in part to help rehabilitate his image and rebut a narrative that “questioned McCabe’s impartiality in overseeing FBI investigations involving former Secretary of State Hillary Clinton”.

After he was fired, Mr McCabe warned the decision extended “the Administration’s ongoing war on the FBI and the efforts of the Special Counsel investigation”. 

“This attack on my credibility is one part of a larger effort not just to slander me personally, but to taint the FBI, law enforcement, and intelligence professionals more generally”, he said.