Special counsel Robert Mueller’s team reportedly met this summer with the author of the controversial, unverified dossier on alleged ties between President Trump and Russia.

Two people familiar with the matter told CNN that members of Mueller’s investigative team met with former MI6 officer Christopher Steele as part of its investigation into Moscow's interference in the 2016 election.

Reuters had reported Wednesday that the dossier had become part of Mueller’s probe.

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The dossier, originally intended as opposition research, was first funded by an anti-Trump GOP group, but a pro-Hillary Clinton Hillary Diane Rodham ClintonWhat Senate Republicans have said about election-year Supreme Court vacancies Bipartisan praise pours in after Ginsburg's death Trump carries on with rally, unaware of Ginsburg's death MORE group began paying for the work when Trump emerged as the Republican nominee.

The U.S. intelligence community said in a report made public in January that they took the allegations made in the dossier seriously, and Trump was briefed on the dossier shortly before taking office by former FBI Director James Comey.

CNN's report comes one day after the leaders of the Senate Intelligence Committee said that they’re still investigating whether there was any collusion between the Trump campaign and Russia during the 2016 presidential race.

Chairman Richard Burr Richard Mauze BurrRep. Mark Walker says he's been contacted about Liberty University vacancy Overnight Defense: Trump rejects major cut to military health care | Senate report says Trump campaign's Russia contacts posed 'grave' threat Senate report describes closer ties between 2016 Trump campaign, Russia MORE (R-N.C.) and ranking member Mark Warner Mark Robert WarnerIntelligence chief says Congress will get some in-person election security briefings Overnight Defense: Trump hosts Israel, UAE, Bahrain for historic signing l Air Force reveals it secretly built and flew new fighter jet l Coronavirus creates delay in Pentagon research for alternative to 'forever chemicals' House approves bill to secure internet-connected federal devices against cyber threats MORE (D-Va.) expressed frustration that their probe had "hit a wall" regarding the dossier, and that they themselves had been unable to speak with Steele.

“My hope is that Mr. Steele will make a decision to meet with either Mark and I or the committee, so we can hear his side of it versus for us to depict in our findings what his intent or what his actions were,” Burr said. “I say that to you, but I also say it to Chris Steele.”