Special counsel John Durham's report released Monday details his investigation of a purported effort by Hillary Clinton's 2016 campaign to tie Donald Trump to Russia but which Durham concludes "did not, all things considered, amount to a provable criminal offense."

Durham reveals in a footnote that he interviewed the former secretary of State in May 2022 as part of his investigation.

The special counsel was looking into whether any crimes occurred in the handling of an uncorroborated piece of US intelligence indicating Russia knew of a Clinton campaign plan to vilify her opponent, Trump, by tying him to the country.

The 2016 intelligence got the attention of then-CIA Director John Brennan, who briefed the Obama White House and referred the issue to the FBI. During the Trump administration, Director of National Intelligence John Ratcliffe released some of Brennan's notes about the intelligence used in his briefing of former President Barack Obama.

Ratcliffe publicly said that the intelligence community never corroborated the Russian claims of a "Clinton Plan" to frame Trump, and didn't know whether it was fabricated.

In her interview with Durham's investigators, Clinton expressed sympathy for Durham's hunt. She calls it, "really sad," adding, "I get it, you have to go down every rabbit hole."

But Durham believes the uncorroborated intelligence should have at least made the FBI question whether it was being used by a political opponent to pursue allegations against the Trump campaign, the report shows.

Clinton called the intelligence that was consuming Durham's time bogus, saying it "looked like Russian disinformation to me."

A spokesman for Clinton didn't respond to a request for comment Monday.

Durham concludes that it would be impossible to prosecute anyone for their handling of the intelligence. He said it "amounted to a significant intelligence failure," but not a crime.