Republicans on the House Judiciary Committee on Tuesday pressed Robert Mueller about the origins of the Russia probe — and whether he ever tried to determine if the author of a dossier on President Trump was telling the truth.

The author, Christopher Steele, is a former British spy who specialized in Russia, and he contributed information to the dossier that he said originated from his Russian sources, including salacious, unsubstantiated tales about Trump.

“You stated in your opening that the organizing principle was to fully and thoroughly investigate Russia’s interference, but you weren’t interested in whether or not they were interfering through Steele and you should have charged him like other people. But you say nothing about this in your report,” Florida GOP Rep. Matt Gaetz declared.

“Do you have any basis as you sit here today to believe that Steele was lying?” he asked, suggesting that the dossier could have been part of a Russian disinformation campaign.

“It’s not my purview,” Mueller replied, refusing to engage with Gaetz, a staunch Trump supporter, on the dossier, which he said had been compiled before his appointment.

“It’s not your purview as to whether or not Steele was lying or whether anti-Trump Russians are lying to Steele?” asked Gaetz, who then flatly stated without providing evidence that Steele was lying.

“Here’s what I’m kind of noticing. When people associated with Trump lied, you threw the book at them. When Steele lied, nothing,” the congressman said, referring to former Team Trump members Michael Cohen, Paul Manafort and Mike Flynn, who were all sentenced to prison for lying to investigators.

Fellow GOP Reps. Jim Jordan of Ohio and Louie Gomert of Texas also followed the party’s strategy of questioning the legitimacy of Mueller’s nearly two-year probe, which resulted in the indictments of roughly three dozen individuals and entities.

Mueller generally declined to engage with their line of questioning, sticking, as directed by the Justice Department, to the contents of his 448-page report.

Republicans have repeatedly charged that the Russia probe was sparked by the Steele dossier, which was partly funded by Hillary Clinton’s campaign and the Democratic Party.

But Mueller said in his report that the 23-month probe was sparked by a wine-soaked sit-down between a low-level Trump aide and an Australian diplomat.

The Trump aide, George Papadopoulos, and Australia’s former high commissioner in London, Alexander Downer, met at the Kensington Wine Rooms in London in May 2016, according to the highly anticipated report.

At that sit-down, Downer said, Papadopoulos told him that the Russians had dirt on Clinton.

Downer informed his superiors, but the Australian government kept mum about the information until July 26, days after WikiLeaks dumped its first load of Team Clinton emails, which Mueller said had been hacked by the Russians.

They passed the information along to officials in the Obama administration.

“The FBI opened its investigation of potential coordination between Russia and the Trump campaign a few days later based on the information’’ from Australia, according to Mueller’s report.