The House select committee investigating the Capitol attack voted on Tuesday to recommend the criminal prosecution of Donald Trump’s former chief strategist Steve Bannon, after he defied a subpoena relating to their inquiry into the 6 January insurrection.

The select committee approved the contempt of Congress citation unanimously, sending the report to the Democratic-controlled House, which is expected on Thursday to authorize the panel to go to court to punish Bannon for his non-compliance.

“It is essential that we get Mr Bannon’s factual and complete testimony in order to get a full accounting of the violence of January 6th and its causes,” said Bennie Thompson, the chairman of the select committee.

“Mr Bannon will comply with our investigation or he will face the consequences,” he said. “We cannot allow anyone to stand in the way of the select committee as we work to get to the facts. The stakes are too high.”

Members on the select committee took the aggressive step against Bannon to sound a warning to Trump White House officials and others connected to the Capitol attack that defying subpoenas would carry grave consequences, according to a source on the panel.

The select committee had issued a bevy of subpoenas to some of Trump’s closest advisers – White House chief of staff Mark Meadows, his deputy Dan Scavino, defense department aide Kash Patel, and Bannon – under the threat of criminal prosecution.

But under orders from the former president and his lawyers, Bannon ignored his subpoena compelling documents and testimony in its entirety. The other three Trump administration aides opened negotiations over the extent of their possible cooperation.

The ramifications for Bannon’s defiance are significant: once passed by the House, the justice department transfers the case to the office of the US attorney for the District of Columbia, which is required to take the matter before a federal grand jury.

In pushing to hold Bannon in contempt of Congress, the select committee has also set up a potentially perilous legal moment for Bannon as he resists the inquiry into what Trump knew in advance of efforts to stop the certification of Joe Biden’s election win.

A successful contempt prosecution could result in up to a one-year sentence in federal prison, $100,000 in fines, or both – although the misdemeanor offense may not ultimately lead to his cooperation and pursuing the charge could still take years.

Bannon remains a key person of interest to House select committee investigators in large part because he was in constant contact with Trump and his team in the days before 6 January, as the former president strategized how to return himself to the Oval Office.

He also appeared to have advance knowledge of the Capitol attack, predicting on his War Room podcast, the day before the insurrection that left five dead and 140 injured: “All hell is going to break loose tomorrow.”

In opening statements ahead of the vote, Republican congresswoman and committee member Liz Cheney said: “Mr Bannon’s and Mr Trump’s privilege arguments do appear to reveal one thing, however: they suggest that President Trump was personally involved in the planning and execution of January 6th. And we will get to the bottom of that.”

But the former chief strategist to Trump indicated to the select committee he would not cooperate with his 23 September subpoena on grounds that communications involving Trump are protected by executive privilege and cannot be revealed to Congress.

The legal argument faces a steep uphill battle with the Biden justice department appearing inclined to adopt a narrow interpretation on executive privilege, previously allowing top Trump justice department officials to testify to Congress about 6 January.

And as the justice department examines the expected referral from the House in finer detail, prosecutors may open Trump to legal jeopardy insofar as he may have obstructed justice by ordering Bannon and other aides to defy the subpoenas.

The select committee said in the contempt report that Bannon had no basis to refuse his subpoena because Trump never actually asserted executive privilege – but also because Bannon tried to use an executive privilege claim for non-executive branch materials.

Within the scope of the subpoena demanding documents and testimony, the report said, included contacts with members of Congress and Trump campaign officials in the days before 6 January, which are ostensibly unrelated to communications between Bannon and Trump.

The contempt report added that even if the select committee accepted his executive privilege claim, the law makes clear that even senior White House officials advising sitting presidents have the kind of immunity from congressional inquiries being claimed by Bannon.

The report further noted: “If any witness so close to the events leading up to the January 6 attack could decline to provide information to the select committee, Congress would be severely hamstrung in its ability to exercise its constitutional powers.”

The prospect of prosecution appears not to have worried Bannon, who spent the day before his deposition date a hundred miles away in Virginia, where he attended a Republican rally that featured a flag purportedly carried by a rioter at the Capitol attack.

Trump lashed out at the select committee after it announced it would vote to hold Bannon in contempt. “They should hold themselves in criminal contempt for cheating in the election,” he said, repeating lies about a stolen election refuted by the justice department.

Still, the select committee’s net appears to be closing in on the former president. Thompson, the chair of the select committee, said on CNN on Thursday that he would not rule out eventually issuing a subpoena for Trump himself.

Maanvi Singh contributed reporting