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The House task force investigating the assassination attempts against former President Trump held its first hearing Thursday.

"They've done a lot of work behind the scenes. They've interviewed dozens of witnesses. They gathered thousands of documents. They've been doing the work to lead up to the hearing, and I know there'll be a lot of interest in that," House Speaker Mike Johnson, R-La., said Tuesday.

"The American people desire and deserve answers, and the task force is working around the clock to deliver them."

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Reps. Mike Kelly and Jason Crow

The Trump assassination attempt task force, led by U.S. representatives Mike Kelly, left, and Jason Crow, right, is holding its first hearing. (Getty Images)

The task force was assembled after unanimous approval in the House, a rare feat in today's partisan environment. 

Its scope was just expanded last week after a foiled second alleged attempt on Trump’s life, this time while the ex-president was golfing at his own course in West Palm Beach.

Thursday’s hearing, however, focused on the July 13 shooting at Trump’s rally in Butler, Pennsylvania.

A 20-year-old gunman opened fire from a rooftop just outside the rally perimeter, killing one attendee and injuring others. Trump was struck in the ear by a bullet and was quickly evacuated offstage by Secret Service agents.

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Witnesses included Edward Lenz, commander of the Butler County Emergency Services Unit; Butler Township Police Patrolman Drew Blasko; Pennsylvania State Police Lt. John Herold; former Secret Service agent Patrick Sullivan; and the Allegheny County medical examiner, Dr. Ariel Goldschmidt.

police standing over shooter thomas crooks

Police stand over Thomas Crooks after he was shot. (Butler Township Police Department)

The task force, led by Chairman Mike Kelly, R-Pa., and ranking member Rep. Jason Crow, D-Colo., has already sent out a flurry of information and document requests to local, state and federal officials.

Lawmakers hope to get to the bottom of how Thomas Matthew Crooks was able to position himself so close to the rally with his weapon despite being noticed by some attendees and even local officials long before he opened fire.

"The communication failures on the day of the event were clearly catastrophic [and] led to what we saw happen that day. So, I anticipate we're going to hear testimony from people who were there, who were part of that process, who can give us information about how those breakdowns occurred," Rep. Laurel Lee, R-Fla., a task force member, said on "Fox News Live" Sunday.

Donald Trump Injured During Shooting At Campaign Rally In Butler, PA

Trump was grazed in the ear during the assassination attempt. (Anna Moneymaker/Getty Images)

The hearing came a day after the Senate Homeland Security and Governmental Affairs Committee released a damning interim report detailing planning and security failures that occurred July 13.

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The report said the Secret Service did not have an adequate chain of command in place for approving security decisions ahead of the rally and failed to coordinate security specifically in relation to the building the shooter fired from.

It accused the Secret Service Counter Sniper Team leader of not going inside or on top of the building and said a sniper team charged with monitoring the area had an obstructed view, among other issues.