Hearing begins on video at 1:03:28.

WASHINGTON — “This is how I’m going to die, defending this entrance,” Capitol Police Officer Aquilino Gonell recalled thinking, testifying at the emotional opening hearing of the congressional panel investigating the violent Jan. 6 Capitol insurrection.

Officer Gonell told House investigators he could feel himself losing oxygen as he was crushed by rioters – supporters of then-President Trump – as he tried to hold them back and protect the Capitol and lawmakers.

He and three other officers gave their accounts of the attack Tuesday, sometimes wiping away tears, sometimes angrily rebuking Republicans who have resisted the probe and embraced Trump’s downplaying the day’s violence by supporters who were challenging his election defeat.

Along with graphic video of hand-to-hand fighting, the officers described being beaten as they held off the mob that broke through windows and doors and interrupted the certification of Democrat Joe Biden’s presidential win. The new committee is launching its probe with a focus on the law enforcement officers who protected them — putting a human face on the violence of the day.

Metropolitan Police Officer Michael Fanone, who rushed to the scene, told the committee – and millions watching news coverage – that he was “grabbed, beaten, tased, all while being called a traitor to my country.” Doctors later told him he’d had a heart attack.

Daniel Hodges, also a D.C. police officer, said he remembered foaming at the mouth and screaming for help as rioters crushed him between two doors and bashed him in the head with his own weapon, injuring his skull.

Capitol Police Officer Harry Dunn said one group of rioters, perhaps 20 people, screamed the n-word at him as he was trying to keep them from breaching the House chamber.

Washington Metropolitan Police Department officer Daniel Hodges wipes his eyes during the House select committee hearing on the Jan. 6 attack on Capitol Hill in Washington on Tuesday. Andrew Harnik/Associated Press

Tensions on Capitol Hill have only worsened since the insurrection, with many Republicans playing down, or outright denying, the violence that occurred and denouncing the Democratic-led investigation as politically motivated. Democrats are reminding people how brutal it was, and how the law enforcement officers who were sworn to protect the Capitol suffered serious injuries at the hands of the rioters.

The officers detailed the horror of their experiences, their injuries and the lasting trauma as they begged the lawmakers to investigate the attack.

“I feel like I went to hell and back to protect them and the people in this room,” Fanone testified.

Pounding his fist on the table in front of him, he said, “Too many are now telling me that hell doesn’t exist or that hell actually wasn’t that bad. The indifference shown to my colleagues is disgraceful.”

The lawmakers on the committee, too, grew emotional as they played videos of the violence and repeatedly thanked the police for protecting them. Democratic Rep. Stephanie Murphy of Florida told them she was hiding near an entrance they were defending that day and “I shudder to think what would have happened had you not held that line.”

Illinois Rep. Adam Kinzinger, one of two Republicans on the panel, shed tears during his questioning. He said he hadn’t expected to become so emotional.

“I think it’s important to tell you right now that you guys may individually feel a little broken,” Kinzinger told the officers. “You guys all talk about the effects you have to deal with and you talk about the impact of that day. But you guys won. You guys held.”

Wyoming Rep. Liz Cheney, the panel’s other Republican appointed by Democratic House Speaker Nancy Pelosi, expressed “deep gratitude for what you did to save us” and raised broader, larger issues.

“The question for every one of us who serves in Congress, for every elected official across this great nation, indeed, for every American is this: Will we adhere to the rule of law, respect the rulings of our courts, and preserve the peaceful transition of power?”

“Or will we be so blinded by partisanship that we throw away the miracle of America?”

U.S. Capitol Police Sgt. Aquilino Gonell, from left, Washington Metropolitan Police Department officer Michael Fanone, Washington Metropolitan Police Department officer Daniel Hodges and U.S. Capitol Police Sgt. Harry Dunn testify before the House select committee hearing on the Jan. 6 attack on Capitol Hill in Washington on Tuesday. Chip Somodevilla/Pool via Associated Press

The House Republican leader, Kevin McCarthy, withdrew the participation of the Republicans he had appointed last week after Pelosi rejected two of them, saying their “antics” in support of Trump, and his lies that he won the election, weren’t appropriate for the serious investigation.

Monday evening, the House voted against a resolution offered by the Republican leader to force his chosen members onto the panel.

McCarthy has stayed close to Trump since the insurrection and has threatened to pull committee assignments from any Republican who participates on the Jan. 6 panel. He has called Cheney and Kinzinger “Pelosi Republicans,” which Cheney has dismissed as “childish.”

Ahead of the hearing on Tuesday, McCarthy again called the process a “sham” and said Pelosi only wanted the questions asked “that she wants asked.”

McCarthy told reporters that Pelosi should be investigated for her role in the security failures of the day but ignored questions about Senate Republican Leader Mitch McConnell, who had identical authority over the Capitol Police and Capitol security officials.

Chairman Bennie Thompson, D-Miss., said the hearing would “set the tone” of the probe, which will examine not only Trump’s role in the insurrection but the groups involved in coordinating it, white supremacists among them.

It will also look at security failures that allowed hundreds of people to breach the Capitol and send lawmakers running for their lives. Some of those who broke in were calling for the deaths of Pelosi and Vice President Mike Pence, who was hiding just feet away from the mob.

Outside of a committee preparation session for the hearing on Monday, Kinzinger told reporters that “for too long, we’ve been pretending that Jan. 6 didn’t happen” and that “when you have lies and misinformation that continue to thrive, it’s essential for us as members of Congress to get to the answers.”

Shortly after the insurrection, almost every Republican denounced the violent mob — and some criticized Trump himself, who told his supporters to “fight like hell” to overturn his defeat. But many have softened their tone in recent months and weeks.

And some have gone further, with Georgia Rep. Andrew Clyde saying a video of the rioters looked like “a normal tourist visit” and Arizona Rep. Paul Gosar repeatedly saying that a woman who was shot and killed by police as she was trying to break into the House chamber was “executed.” Others have falsely claimed that Democrats or liberal groups were responsible for the attack.

The officers testifying have become increasingly politically active in recent months, and went from office to office in May to lobby Senate Republicans to support an outside commission to investigate the insurrection. The Senate GOP ultimately rejected that effort, though that panel would have been evenly split between the parties.

Associated Press writers Eric Tucker, Kevin Freking and Padmananda Rama contributed to this report.