Republican congressman Adam Kinzinger has said that bombshell testimony given by Cassidy Hutchinson to the January 6 hearings last week has inspired more witnesses to come forward and the committee is getting more new evidence by the day.

The panel is investigating the events surrounding the 2021 attack on the US Capitol by a mob of Donald Trump supporters. Kinzinger is one of two Republicans serving on the panel which has publicized explosive testimony about the insurrection and an apparent plot to subvert the 2020 election, which Joe Biden won.

Last week Hutchinson, a former top aide to Trump’s chief of staff, Mark Meadows, gave sworn testimony that painted the former president as a violent and unstable figure desperately seeking to cling to power.

“There will be way more information and stay tuned,” Kinzinger told CNN’s State of the Union co-anchor Dana Bash. “Every day, we get new people that come forward and say, ‘Hey, I didn’t think maybe this piece of a story that I knew was important, but now I do see how this plays in here.’”

Kinzinger also pushed back on doubts raised about Hutchinson’s testimony, including from Secret Service sources that have disputed her account that Trump tried to grab the steering wheel of the presidential SUV when the Secret Service refused to let him go to the Capitol after the rally.

Robert Engel and Tony Ornato, the Secret Service agents who were in the car, are reportedly prepared to testify that they were not assaulted by Trump and he did not try to grab the steering wheel.

“We certainly would say that Cassidy Hutchinson has testified under oath,” Kinzinger said. “We find her credible, and anybody that wants to cast disparagements on that, who were firsthand present, should also testify under oath and not through anonymous sources.”

At least two more hearings are scheduled this month that aim to show that Trump illegally directed a violent mob toward the Capitol, and failed to direct supporters to stop once the siege began.

In a separate interview, another committee member, Congressman Adam Schiff, said: “There’s certainly more information that is coming forward … we are following additional leads. I think those leads will lead to new testimony.”

Schiff added that part of the reason the committee had wanted to put Hutchinson to testify would be to encourage others to do so as well. “We were hoping it would generate others stepping forward, seeing her courage would inspire them to show the same kind of courage,” he said.

As Trump reportedly mulls declaring himself a candidate for 2024 as soon as this month – a tactic, many believe, for heading off potential criminal charges – Schiff also responded to comments by Liz Cheney, committee vice-chair, that criminal referrals could result from the hearings.

“For four years, the justice department took the position that you can’t indict a sitting president. If the department were now to take the position that you can’t investigate or indict a former president then a president becomes above the law,” Schiff said. “That’s a very dangerous idea that the founders would have never subscribed to.”