House Oversight Committee Chairman James Comer, R-Ky., has clearly struggled at times to control the flow and direction of his committee's unruly first impeachment inquiry hearing.

Republicans appeared unprepared for Democrats' procedural tricks. Comer has repeatedly sniped at Democrats during their testimony -- which is unusual for a committee chair.

"Can you read a bank statement?" Comer could be heard saying when Rep. Summer Lee, D-Penn., mocked Republicans and claimed they hadn't found a "smoking gun."

After Rep. Dan Goldman, D-N.Y., requested to add six excerpts from Hunter Biden's former business partner Devon Archer's transcribed interview into the record, Comer replied, "It's been entered twice. If you want to enter it again, go ahead."

Some of his own members have shouted over him and contributed to the raucous nature of this hearing.

"Democrats are the party of shutdowns. You love shutdowns," Rep. Marjorie Taylor Greene, R-Ga., called out when Lee was listing off the number of federal workers in each Republican members' district who would feel the impact of a shutdown.

The day has been reminiscent of some of the early Trump impeachment hearings in 2019, when former Judiciary Committee Chairman Jerry Nadler, D-N.Y., struggled to spar with Rep. Jim Jordan, R-Ohio, and some of his members privately complained about his performance.

--ABC News' Benjamin Siegel

Like Democrats who spoke before him, Rep. Dan Goldman, D-N.Y., reiterated that the hearing has no witnesses testifying with "direct knowledge of the evidence to determine that there is a basis for this impeachment inquiry."

"And this is an impeachment inquiry," he continued.

There has been no new evidence or knowledge so far in this hearing, he said.

"So why don't we have some of the fact witnesses here?" Goldman said. "The reason is, you bring in the fact witnesses and your case goes down the drain."

Rep. Katie Porter, D-Calif., made a point to highlight House Speaker Kevin McCarthy's past remarks regarding an impeachment inquiry.

"A veteran of several impeachments said an impeachment without a floor vote by the Congress would create a process completely devoid of any merit or legitimacy," Porter said.

She held up a poster featuring a photo of McCarthy and his quote, made over former President Donald Trump's 2019 impeachment inquiry.

"This House vote didn't happen," Porter continued. "We have not followed what the speaker himself, Mr. McCarthy, has said is the process that we should be following so that an impeachment inquiry would have merit or legitimacy. Which is something that I think all Americans on both sides of the aisle should expect investigations or inquiries like this to have."

After a brief recess, a Republican on the House Oversight Committee pushed back against Democrats' criticism that the hearing was unnecessary and improper.

Rep. William Timmons R-S.C. contended that there was enough evidence against Hunter Biden to start the inquiry. Timmons acknowledged that the evidence was "circumstantial" but stressed that lawmakers needed to do due diligence.

"The Congress has a duty to determine whether Joe Biden was a loving father taken advantage of by a delinquent son or a knowingly participant complicit in the scheme and financially compensated for his role. That's why we are here today, to answer that simple question," he said.

Timmons added that the panel will subpoena Hunter Biden's "personal bank records, various business records, invoices and contracts."

"We are doing this because the Department of Justice, FBI and the IRS refuse to do that their job," he claimed, without evidence.