Rep. Devin Nunes, R-Calif., said Thursday his team is "prepared now" to submit a criminal referral to the Justice Department focusing on the origins of the Trump-Russia investigation.

The ranking member of the House Intelligence Committee has been teasing a referral for months, and earlier this week he predicted its delivery by the end of next week.

During an interview on Fox Business, Nunes said there will be one referral to start, and possibly more to follow, after President Trump said Wednesday he plans to release the unredacted Foreign Intelligence Surveillance Act warrants that jump-started the Russia probe.

"My major concern now is that the FBI and DOJ falsely claimed that this investigation didn’t begin until late July," Nunes told anchor Maria Bartiromo. "We now know for certain that that’s not true, we’re still trying to get to the bottom of that. Of course there are still documents that need to come out, but we are prepared and are now drafting a criminal referral … we wanted to wait until the Mueller report came out so that we could just — if there was anything in there that might be of interest, but I think we’re prepared now to at least submit our first criminal referral."

He said he thinks this referral would "grab everybody that we need to grab to make sure that there’s a proper investigation done," but noted there may be more to "to supplement" the first.

Nunes has not named anyone who could appear in a referral, but he has railed against what he says is collusion between the Democrats and the Russians, pointing to use of the unverified Trump dossier by the FBI to obtain FISA warrants to spy on onetime Trump campaign official Carter Page as proof of an unraveling operation to undermine the president. That dossier, compiled by British ex-spy Christopher Steele, was funded in part by Hillary Clinton's campaign and the Democratic National Committee.

Testimony from DOJ official Bruce Ohr, who served as an unofficial backchannel between Steele and the FBI, which was made public this year confirmed that top Justice Department officials knew about the dossier earlier than first thought, and that among those who knew was Andrew Weissmann, who went on to become the top deputy of special counsel Robert Mueller.

“Some of the biggest challenges that we had is because they used our counterintelligence capabilities — these secret capabilities that are really only supposed to be used to go after terrorists and other bad guys, they actually turned it on a political campaign, and that’s where they first went wrong," Nunes told Bartiromo, while talking about a "DOJ and FBI run amok.”

"Now, my estimation is they used what’s called ‘counterintelligence’ because they could keep it siloed and hidden from the American people and from the rest of FBI and DOJ … they opened up a counterintelligence investigation into the Trump campaign because they could use these secret capabilities," he added. "Then, of course, we all know the story about how they went to the FISA court, they mislead the FISA court, lied to the FISA court in order to get a warrant on a Trump campaign associate so that they then could get a bunch of emails, phone calls, and records into the campaign."

Mueller concluded his nearly two-year-long Russia investigation and sent his final report to the Justice Department. Attorney General William Barr shared a summary of Mueller's report to Congress on Sunday that said Mueller's team found no collusion between the Trump campaign and Russia. Mueller also declined to determine whether Trump obstructed justice, and Barr said he and Deputy Attorney General Rod Rosenstein concluded there was insufficient evidence to show the president committed a crime.

Nunes had said he wanted to see what was in Mueller's report before taking criminal referral action. Although Congress has not seen the full report, and Democrats are demanding its release within a week, a Justice Department official told Reuters that Barr plans to make public a version of it within "weeks, not months."

Nunes has looked to Barr, who on Feb. 14 became attorney general, to make headway toward completing an investigation begun last year by a joint GOP-led task force comprising the Judiciary Committee and the Oversight Committee. Key to this effort, which has been bolstered by intelligence panel Republicans, is investigators looking over roughly 15 transcripts of interviews conducted by the task force last year.