Rep. Melanie Stansbury, D-N.M., was the latest Democrat to display Trump's social media posts behind her as she accused Republicans of doing his bidding.

"It's a campaign strategy ... we see the long arms -- but tiny hands -- of Donald Trump, and his fingerprints all over this impeachment," she said.

Republicans have largely ignored Democrats' jabs against Trump and his indictments, though one GOP lawmaker taunted Democrats.

"I love the fact that Trump lives rent-free in the Democrats' heads every day, that is a beautiful thing, even though we are here talking about the impeachment inquiry of Joe Biden," Rep. Lisa McClain, R-Mich., said.

During her time to ask questions, Rep. Alexandria Ocasio-Cortez, D-N.Y., said the allegations are "extremely serious," but called the hearing an "embarrassment."

She established that none of the four witnesses can give any firsthand witness account of any crimes committed by the president.

"This is an embarrassment. It is an embarrassment to the time and people of this country," she said.

Rep. Glenn Grothman, R-Wis., followed by saying he was concerned about the "seriousness of the allegations."

"We have all sorts of smoke, maybe not fire," he said. "It deserves a strong response from this body."

Rep. Shontel Brown, D-Ohio, asked Democratic witness Michael Gerhardt what he believes is the "primary flaw" in the Republican claims about President Biden.

"Well, I suppose I can say a lot. The problem is the dots are not connected," Gerhardt replied. "The name repeated most often is Hunter Biden, not President Biden. And the point of an impeachment inquiry is not about a president's son, it has to be about the president himself and I don't think those dots connected. Lots of assumptions and accusations, not evidence."

Rep. Jim Jordan, R-Ohio, chairman of the House Judiciary Committee, called testimony from Hunter Biden's former business partner, Devin Archer, "the most telling evidence" of the president's potential involvement in an "influence-peddling scheme."

Jordan said that a Ukrainian prosecutor investigating a Ukrainian company tied to Hunter Biden's was fired after Hunter Biden received a request from Burisma's top executive and then called his father, who "leveraged $1 billion of American tax money" to get the prosecutor fired.

But a review of Archer's testimony, detailed in a publicly-released transcript, shows that Jordan left out key parts of Archer's testimony and mischaracterized other parts of it.

Among other things, Archer said the request from Burisma's top executive wasn't specific to the prosecutor's firing, and he wasn't even sure that Hunter Biden called his father after getting the request.

--ABC News' Mike Levine and Luc Bruggeman

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