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House Republicans are demanding to know how a gunman was able to wound former President Donald Trump during a deadly sniper attack at a campaign rally in Pennsylvania.
Oversight Committee chairperson James Comer called for a Secret Service briefing on the incident, he said in a statement posted on the committee's website.
The Kentucky Republican also invited Secret Service Director Kimberly Cheatle to voluntarily appear at a July 22 hearing.
"There are many questions and Americans demand answers," Comer said.
Rep. Mark Green, who chairs the Homeland Security Committee, said in a Sunday letter to committee Secretary Alejandro Mayorkas that Trump might have been killed if the trajectory of the bullet that hit him had been "slightly different."
"The seriousness of this security failure and chilling moment in our nation's history cannot be understated," wrote the Tennessee Republican.
House Speaker Mike Johnson vowed the GOP-controlled chamber would conduct a "full investigation" and have Cheatle and other officials from the Department of Homeland Security and FBI testify "before our committees ASAP."
The Secret Service didn't have a speaker at a late-night Saturday news conference at which FBI Special Agent in Charge Kevin Rojek said it was "surprising" that the gunman was able to fire at the stage before being killed by the Secret Service, according to the Associated Press.
The Secret Service didn't immediately respond to a request for comment Sunday, but a spokesperson denied reports that it turned down Trump campaign requests for additional security at the rally at the Butler Farm Show grounds.
"This is absolutely false. In fact, we added protective resources & technology & capabilities as part of the increased campaign travel tempo," Anthony Guglielmi wrote on social media Sunday morning.
The shooter, 20-year-old Thomas Matthew Crooks of Bethel Park, Pennsylvania, opened fire with an AR-style semiautomatic rifle from a rooftop less than 165 feet from where Trump was speaking around 6:15 p.m. Saturday.
Trump was shot through his upper right ear, and rally spectator Corey Comperatore, 50, was killed, with Pennsylvania Gov. Josh Shapiro saying Sunday that he "died a hero" while shielding his family from the gunfire.
Two other men were critically wounded and remained hospitalized.
Two unidentified law enforcement officials told AP that members of the Secret Service's counter-sniper team and counterassault team were at Trump's rally.
The heavily armed counterassault team, code-named "Hawkeye," is responsible for neutralizing threats so other agents can shield and remove the person or people being protected.
The counter-sniper team, code-named "Hercules," uses powerful binoculars and sniper rifles to do the same thing from a distance.
The FBI said Saturday night that it was leading the law enforcement probe into Saturday's shooting and Attorney General Merrick Garland said the Justice Department "will bring every available resource to bear to this investigation."