Rep. Devin Nunes said Republicans plan to grill former special counsel Robert Mueller about his top prosecutor when he testifies in an open setting later this month.

Andrew Weissmann, who was known as Mueller's "pitbull," will be the subject of multiple lines of inquiry, the ranking member on the House Intelligence Committee told Fox News' Bill Hemmer on an episode of the "Hemmer Time" podcast.

In a preview of what he and his GOP colleagues will ask on July 24, Nunes said Mueller will be pressed on why the FBI withheld from his panel that Weissmann briefed Associated Press reporters in 2017 on "something to do with the Trump-Russia investigation" before the Mueller team had assembled. Nunes said the House Intelligence Committee, which was investigating Russian election interference, was never told why Weissmann was talking to these journalists.

He indicated this is significant as Weissmann was briefed on British ex-spy Christopher Steele's dossier, which contained salacious and unverified claims about President Trump's ties to Russia, in the summer of 2016. Nunes said Weissmann "was in the chain of custody of the major piece of evidence that started this investigation."

The Daily Caller reported in July 2018 that documents show Weissmann arranged the April meeting with four AP reporters and other FBI officials meeting to discuss former Trump campaign chairman Paul Manafort. In a pre-hearing trial, FBI special agent Jeffrey Pfeiffer suggested the meeting the FBI may have conducted its May 2017 raid of a storage locker bring rented by Manafort based on an AP tip.

“Associated Press journalists met with representatives from the Department of Justice in an effort to get information on stories they were reporting, as reporters do. During the course of the meeting, they asked DOJ representatives about a storage locker belonging to Paul Manafort, without sharing its name or location," AP spokeswoman Lauren Easton told the outlet.

Manafort is serving prison time after being found guilty of federal tax fraud, bank fraud, and foreign lobbying violations due to charges stemming from Mueller's investigation.

Calling the investigation an "obstruction of justice trap" that began without evidence of collusion between the Trump campaign and Russia, Nunes called for accountability. "These are all a bunch of dirty cops and I'll tell you," the California Republican said. "I'll tell you — some of them better go to jail, or we're going to go down in a spiral in this country because you will not have a Republican that will trust the FBI or the Department of Justice for generations to come."

According to Michael Wolff's book Siege, Weissmann, who recently scored a book deal, led the initiative to draft a three-count obstruction of justice indictment against Trump, which Mueller's spokesman denied existed.

Mueller was originally scheduled to testify before the House Intelligence and Judiciary Committees next week, but after members complained about strict limits for questioning, Democratic Judiciary Committee Chairman Jerry Nadler of New York and Democratic Intelligence Committee Chairman Adam Schiff of California announced on Friday that a deal had been struck for a less stringent hearing to take place on July 24.

Trump disparaged Mueller and top ex-officials on Saturday, claiming that the special counsel's team engaged in "illegal" activity by deleting text messages exchanged between former FBI officials Peter Strzok and Lisa Page. "This is one of the most horrible abuses of all. Those texts between gaga lovers would have told the whole story. Illegal deletion by Mueller. They gave us 'the insurance policy,'" Trump tweeted.

Strzok and Page were said to be involved in an affair as they sent each other text messages that displayed disdain for Trump while they were involved in the Hillary Clinton emails and Russia investigations. Strzok was fired from the FBI in August 2018 and Page resigned a couple months earlier.

Mueller’s report, released by the Justice Department with redactions in April, concluded that Russia interfered in the 2016 election but did not establish that any members of the Trump campaign criminally conspired with the Russians in these efforts. Mueller did not reach a conclusion on obstruction of justice, but Attorney General William Barr and then-Deputy Attorney General Rod Rosenstein concluded there was insufficient evidence for such a crime.

Barr is now engaged in investigating the origins of the Russia investigation and tasked U.S. Attorney John Durham with leading the effort. That inquiry is being supplemented by Justice Department Inspector General Michael Horowitz's investigation into alleged abuse of the Foreign Intelligence Surveillance Act, which is looking into Steele and his dossier.

Steele's dossier on Trump was used by the FBI to obtain FISA warrants to surveil onetime Trump campaign aide Carter Page.

Four FISA warrant applications and renewals were filed from October 2016 through June 2017 against Page. The applications relied heavily on the unverified dossier compiled by Steele, who was hired by Fusion GPS. The opposition research firm was hired by Marc Elias of the Perkins Coie law firm at the behest of the Clinton presidential campaign. Steele and Fusion GPS shopped the research around to various government figures, including one skeptical State Department official, as well as the media in the run-up to the 2016 election.