Attorney General William Barr signaled that federal officials involved in launching the investigation into Russia’s interference in the 2016 election and its links to the Trump campaign could face criminal prosecution.

As part of a wide-ranging interview with Fox News, the attorney general said a federal prosecutor appointed to review the origins of the inquiry, later headed by Justice Department special counsel Robert Mueller, has so far found “troubling” evidence of possible abuses.

“My own view is that the evidence shows that we’re not dealing with just the mistakes or sloppiness,” Barr said Thursday. “There was something far more troubling here. We’re going to get to the bottom of it. And if people broke the law and we can establish that with the evidence, they will be prosecuted.”

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The attorney general's remarks represent the most extensive public assessment yet of Connecticut U.S. Attorney John Durham’s work since his appointment last year.

Durham, a mob-busting federal prosecutor for more than three decades, has been assisting the attorney general to determine whether federal investigators acted appropriately in the early stages of the now-completed inquiry into Russia's interference campaign. Barr announced the review after expressing concerns about the FBI's use of surveillance.

"Spying on a campaign is a big deal," Barr told lawmakers last year. "I think spying did occur. The question is whether it was adequately predicated."

President Donald Trump, who has voiced enthusiastic support for Durham's inquiry, has long denounced the Russia investigation as a "witch-hunt." Mueller's two-year investigation resulted in the conviction of a half-dozen former Trump aides.

Read the report:Special counsel Robert Mueller's report into President Trump, Russian interference

"I think the president has every right to be frustrated," Barr said in the Fox interview, "because I think what happened to him was one of the greatest travesties in American history."

While the attorney general asserted that investigators had no "basis" to launch the investigation into the Trump campaign, the Justice Department's inspector general concluded last year that the FBI was legally justified in launching its inquiry.