A man who was a Princeton University student when the FBI arrested him on charges related to the U.S. Capitol riot pleaded guilty on Monday to joining a mob's attack on police officers during one of the most violent clashes on Jan. 6, 2021.

Larry Fife Giberson was on the front lines when rioters attacked police officers in a tunnel on the Capitol's Lower West Terrace. Giberson, 22, of Manahawkin, New Jersey, waved other rioters into the tunnel and then joined in a coordinated push against officers guarding an entrance to the building, according to a court filing.

Giberson tried in vain to start a chant of “Drag them out!” and then cheered on rioters using weapons and pepper spray against police in the tunnel, according to an FBI’s agent affidavit. Giberson remained in the area for roughly an hour, the affidavit says.

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Giberson pleaded guilty to a felony charge of interfering with police during a civil disorder, court records show. U.S. District Judge Carl Nichols is scheduled to sentence him on Nov. 1. The judge allowed him to remain free until his sentencing.

Giberson was enrolled at Princeton as an undergraduate when he was arrested in March on riot-related charges. On Monday, a university spokesperson declined to answer questions about Giberson’s enrollment status.

Charles Burnham, an attorney for Giberson, didn't immediately respond to emails and a telephone call seeking comment.

Giberson was wearing a “Make America Great Again” hat and a Trump flag around his neck when he joined the Jan. 6 attack, which disrupted the joint session of Congress for certifying President Joe Biden's electoral victory over Donald Trump.

The FBI posted images of Giberson on social media to seek the public’s help in identifying him. Online sleuths also posted images of Giberson using the “#DragThemOut” hashtag moniker.

Investigators matched photos of Giberson from the Capitol to several images found on Instagram and Princeton University’s website, according to the FBI.

Also on Monday, a Florida man was arrested on charges that he assaulted several police officers outside the Capitol during the riot. Videos captured Marcus Clint Martin applying first aid to an injured rioter and then shoving two officers who tried to help, the FBI said.

Other videos show Martin, 32, of Blountstown, Florida, piling onto an officer who was knocked over and removing metal barriers after chasing officers away from their positions in front of the Capitol, according to the FBI.

Martin was arrested in Panama City, Florida, on charges including civil disorder and assaulting, resisting or impeding police. There was no lawyer immediately listed in the court docket for Martin.

Approximately 1,100 people have been charged with federal crimes related to the Capitol riot. More than 600 of them have pleaded guilty. Over 100 others have been convicted by judges or juries after trials in Washington, D.C.