Adam Kinzinger, one of two Republicans on the special committee investigating the deadly 6 January US Capitol attack, said on Sunday the pursuit of a criminal contempt referral against Steve Bannon was “the first shot over the bow” for allies of Donald Trump defying subpoenas to testify.

“It’s very real, but it says to anybody else coming in front of the committee, ‘Don’t think that you’re going to be able to just kind of walk away and we’re going to forget about you’,” Kinzinger, a vocal critic of the former president, told CNN’s State of the Union.

He added that the committee would not rule out calling Trump himself to testify, though he acknowledged that such a move was not imminent.

Bannon, Trump’s former chief strategist, has declined to appear before the committee, or respond to the subpoena demanding documents and testimony, claiming executive privilege. The committee will decide on Tuesday whether to make a criminal contempt referral to the full House of Representatives.

Kinzinger, an Illinois congressman who was one of 10 House Republicans to vote for Trump’s impeachment in January following the insurrection, also said that Joe Biden was right to call for the prosecution of those who resisted subpoenas. Republican criticism of the president’s comments forced the justice department to issue a rare statement on Friday reaffirming its independence from the White House.

“The president has every right to signal, I think he has every right to make it clear where the administration stands. God knows the prior administration every two hours was trying to signal to the justice department,” Kinzinger said, referring to Trump’s prolific pressuring of the DOJ.

“But that has to do with other pretty horrific things, and I think the president has made it clear that we need answers to this. The vast majority of Americans agree, so this potential criminal contempt referral for Steve Bannon is the first shot over the bow.”

The 6 January committee has issued a number of subpoenas in recent days and weeks to former Trump acolytes or administration officials thought to have key knowledge of the events of the day.

Last week’s subpoena for the former top DOJ official Jeffrey Clark was seen as an escalation of its investigation into Trump’s efforts to overturn his election defeat and subsequent false claims that he was cheated out of victory, otherwise known as the big lie.

The Guardian reported earlier this month that Trump had directed aides including Bannon, the former White House chief of staff Mark Meadows, deputy chief of staff Dan Scavino and defense department aide Kash Patel not to testify.

Trump granted clemency to Bannon over federal fraud charges in one of his last acts before leaving office on 20 January.

Kinzinger was also asked if Trump would receive a subpoena.

“We want to make sure we’re getting every piece of this puzzle, that’s going to include people that have already come in talking to us, it’s going to include people that we’ll potentially subpoena in the future, whose names you probably never heard [and] will have a very good incentive to come in and talk,” he said.

“That begins to put the building blocks in this together. Speaking honestly, if we subpoena all of a sudden the former president, we know that’s going to become kind of a circus, so that’s not necessarily something we want to do up front. But if he has pieces of information we need, we certainly will.”