A Republican senator suggested in a private conversation Saturday, without evidence, that the FBI knew more about the planning before the Jan. 6 Capitol riot than it has revealed so far, according to a video obtained by The Washington Post.

The comments from Sen. Ron Johnson (R-Wis.), made after a political event at a Wauwatosa, Wis., hotel, reflect the spread of an unfounded claim that has traveled from far-right commentators to Tucker Carlson’s Fox News show to the highest levels of the GOP.

“I don’t say this publicly, but are you watching what’s happening in Michigan?” Johnson said while discussing the Capitol attack with some of the event’s attendees. “. . . So you think the FBI had fully infiltrated the militias in Michigan, but they don’t know squat about what was happening on January 6th or what was happening with these groups? I’d say there is way more to the story.”

Johnson’s Michigan comment appears to be a reference to the alleged kidnapping plot targeting Gov. Gretchen Whitmer (D) that was disclosed by state and federal authorities in October. Some defendants have recently argued in court that they were entrapped by FBI operatives who stoked their anger against Whitmer, facilitated meetings and paid for hotels and other costs related to the scheme. Without that involvement, those defendants have argued, they would have had no intention of harming Whitmer.

No credible evidence has emerged that the FBI had detailed foreknowledge of a violent assault on the Capitol or that its agents or operatives played a role in fomenting it. No specific claim of FBI involvement has surfaced in court filings made in the hundreds of cases filed against alleged Capitol assailants.

But the allegations have persisted in recent weeks as Republican supporters of former president Donald Trump, who falsely claimed the 2020 presidential election was stolen and encouraged his supporters to march on the Capitol as Congress counted electoral votes on Jan. 6, have consistently sought to finger other culprits for the breach of the Capitol.

In the early hours and days after the riot, some Trump supporters sought to blame left-wing provocateurs. More recently, House Republicans have made the claim that House Speaker Nancy Pelosi (D-Calif.) is at fault.

And Johnson, one of Trump’s most fervent congressional supporters, has for months raised numerous questions about the circumstances surrounding the attack, including the security failures and the nature of the events. He has taken exception, for instance, with describing the attack as an “armed insurrection.”

In the recording captured Saturday, Johnson explained his view that “by and large those folks were peaceful protesters” and that the news media and Democrats are “painting 75 million Americans who voted for Trump as attached with domestic terrorists.”

“I’m just pushing back on that narrative,” he said, adding that he was “not happy with those guys that stood on the Capitol and created the acts of violence. . . . I’ve said that repeatedly and strongly.”

Johnson’s comments questioning the FBI’s knowledge before the riot, however, are new.

While an FBI field office in Norfolk issued a report the day before the riot that warned about calls for violence at the Capitol on an Internet message board, it went unheeded by Capitol Police and other agencies. The report did not reference confidential informants or undercover agents.

A report that two Senate committees issued in June cited “critical breakdowns involving several federal agencies,” including the FBI, and it faulted those agencies for not issuing more-formal warnings that could have improved the security posture. It said the FBI did not take seriously other online messages that suggested violence at the Capitol was a real possibility.

Asked whether Johnson believes the FBI played a role in encouraging the attack or sat by while it was planned and executed, Johnson spokeswoman Alexa Henning pointed to the Senate report’s findings indicating that the Justice Department, of which the FBI is part, had failed to create an “integrated security plan” and said the senator was simply asking key questions in his comments over the weekend.

“The revelation of the depth of the FBI’s involvement in the Governor Whitmer plot raises questions as to whether it had infiltrated Jan. 6 agitator groups as well,” Henning said in a statement. “The senator continues to call on the FBI and DOJ to be transparent. To date, they have not been.”

The FBI declined to comment. Director Christopher A. Wray defended the bureau in March, saying the Norfolk report was appropriately handled as “unverified” information, but he said internal intelligence-sharing practices would be reviewed in light of the violence on Jan. 6.

The alleged Michigan plot does illustrate that the bureau has attempted to infiltrate and disrupt domestic extremist groups, which Wray called a “metastasizing” threat in testimony to Congress.

Right-wing websites first claimed in June that undercover FBI agents or informants were among those who breached the Capitol, allegations that spread quickly through the conservative media ecosystem.

The claims were based on the false assumption that those named in numerous court filings as “unindicted co-conspirators” were federal agents or informants. Carlson, for instance, said on his June 15 show that “in potentially every single case, they were FBI operatives.”

In fact, under federal case law, federal prosecutors cannot refer to federal operatives as “co-conspirators,” because they are acting on behalf of the government, not as part of the conspiracy. Instead, “unindicted co-conspirators” are referred to as such for other reasons, including a lack of evidence to file charges or an after-the-fact cooperation agreement with prosecutors.

But some far-right House Republicans have spread the claims, including Rep. Matt Gaetz (R-Fla.), who sent a letter to Wray the day after Carlson’s show aired asking “to what extent” the agency had infiltrated key “militia groups” and whether operatives were “merely passive informants or active instigators” on Jan. 6.

A day later, Rep. Louie Gohmert (R-Tex.) repeated the allegations on the House floor, calling them “scary stuff” and “Putin kind of activity.” Gaetz has not received a reply to his letter, an aide said Monday.

But those suggestions have not publicly spread into the ranks of Senate Republicans, who have been less inclined than their House colleagues to question the evidence-based narrative surrounding Jan. 6.

At other points in the conversation Saturday, Johnson criticized two Republicans appointed by Pelosi to the House select committee investigating the Capitol attack. Reps. Liz Cheney (R-Wyo.) and Adam Kinzinger (R-Ill.), he said, are “trying to paint with the same broad brush that the media and Democrats want” to portray those marching on the Capitol as “domestic terrorists.”

In another provocative comment, Johnson said Saturday that Republican and Democratic congressional leaders shared blame for the Capitol breach, referencing the lax security around the Capitol perimeter as he criticized the House committee as a “total sham.”

“Are they going to talk about the culpability of congressional leadership, both sides?” he said. “No. . . . They won’t even bring it up.”

That claim of shared culpability is at odds with the arguments of House Republicans, including Minority Leader Kevin McCarthy (R-Calif.), who have sought to blame Pelosi for the security lapse in recent weeks as House Democrats launched the select committee. But Johnson suggests that the Senate majority leader at the time, Sen. Mitch McConnell (R-Ky.), was also at fault.

In fact, neither Pelosi nor McConnell is directly in charge of Capitol security. The Capitol Police force has primary responsibility for securing the campus, and under federal law its chief reports to the Capitol Police Board, which includes the House and Senate sergeants-at-arms, who are appointed respectively by the House speaker and Senate majority leader.

The two sergeants-at-arms on duty Jan. 6, Paul D. Irving for the House and Michael C. Stenger for the Senate, did not identify any direct leadership involvement in the security planning during their testimony to the Senate earlier this year. The Senate’s final report did not single out either leader for blame.

Asked about Johnson’s claims, Pelosi spokesman Drew Hammill pointed to a recent statement from the speaker’s office calling the GOP campaign to blame Pelosi an act of “deflection, distortion, and disinformation” and a “pathetic attempt to distract” from the select committee’s work.

Doug Andres, a McConnell spokesman, declined to comment.

Henning noted that Johnson has spoken frequently about how congressional leaders “bear the ultimate responsibility” for the Capitol’s security and has said their role should be investigated by an outside entity.

“He has said from the start that any investigation must be completely independent and Nancy Pelosi cannot be given unilateral authority to select all staff and pick those who will be on a commission or committee,” she said.

Johnson was among the Republicans who voted in May to oppose an equally divided bipartisan investigative commission, blocking its further consideration in the Senate.

The video of Johnson’s remarks was taken by Bridget Kurt, a 49-year-old Atlanta resident and hospice employee who was staying at the Radisson hotel in Wauwatosa while visiting family. She said she approached Johnson in the hotel bar after the political event ended and the premises were reopened to the public.

Kurt said she was compelled to confront Johnson as a lifelong Republican who has been dismayed with party leaders’ handling of the coronavirus pandemic and the Jan. 6 attack.

“I am so tired of the conspiracy theorists and the Trumpsters destroying our country, our world and our Republican Party,” said Kurt, a Wisconsin native who said she campaigned for Paul D. Ryan in the former House speaker’s early congressional races. “It’s sad, because Wisconsin is better than this.”

Johnson, who is nearing the end of his second term and has not yet announced whether he plans to seek reelection, has been a prominent voice among elected Republicans urging skepticism of coronavirus vaccinations, questioning potential side effects and vocally opposing vaccine mandates.

“It’s time for Americans to reclaim their freedom,” he said in a recent statement opposing President Biden’s vaccination rules for federal employees.

Kurt is heard addressing Johnson at the end of the four-minute recording: “I just want to let you know there truly is a surge in Georgia. I work in hospice. So I just want to make sure you’re encouraging people to get the vaccine.”

“I’m not going to do that,” Johnson responded as his supporters jeered Kurt. “I don’t encourage or discourage.”

Before leaving the room, Kurt said: “But you’re saying things that are counterproductive and not scientific. So I just wanted you to know.”