In police radio traffic recorded about an hour after yesterday’s shooting, callers can be heard describing a man in jeans and a black shirt wielding a rifle on top of a building near the event.
Investigators do not have anyone in custody and had yet to identify a suspect.
Authorities have not commented on a potential motive for the killing, which United States President Donald Trump called a “dark moment for America,” and which follows a spate of political violence that has shaken the nation and deepened partisan divides.
Kirk, 31, was an ardent Trump supporter and a prominent conservative voice, amassing a broad following through his work with Turning Point USA, a youth organisation.
Vice-President JD Vance dropped his plan to attend the 9/11 memorial in New York and instead flew to Utah to be with Kirk’s family, and to fly Kirk’s remains to his home state of Arizona aboard Air Force Two.
In the hours after the killing, officials said they had taken two people into custody and later released them, concluding that the two had “no current ties to the shooting”.
In video footage captured at the scene, Kirk could be seen suddenly jerking backward as blood poured from his neck. The 31-year-old was rushed to a hospital, and Trump later announced his death.
At a memorial service for the 24th anniversary of the September 11, 2001, attack on the Pentagon, Trump announced he would posthumously award Kirk the Presidential Medal of Freedom.
“Before we begin, let me express the horror and grief so many Americans at the heinous assassination of Charlie Kirk have felt,” Trump said.
“Charlie was a giant of his generation, a champion of liberty and an inspiration to millions and millions of people.
“Our prayers are with his wonderful wife, Erika, and his beautiful children, fantastic people they are.
“We miss him greatly, yet I have no doubt that Charlie’s voice and the courage he put into the hearts of countless people, especially young people, will live on.”
Trump then announced he would be awarding Kirk the highest civilian honour in the US.
“The date of the ceremony will be announced, and I can only guarantee you one thing, that we will have a very big crowd. Very, very big,” Trump said, before moving on to his remarks for the 9/11 attacks.
Trump also ordered flags flown at half-staff to honour Kirk and released a video message from the Oval Office yesterday in which he remembered Kirk as a “martyr for truth and freedom” and a “truly Great American Patriot”. In the same video, Trump blamed the rhetoric of the “radical left” for Kirk’s killing.
“This kind of rhetoric is directly responsible for the terrorism we’re seeing in our country today, and it must stop right now,” said Trump.
Utah Governor Spencer Cox (Republican) called the attack “a political assassination”.
The State Department will “undertake appropriate action” against foreigners who praise, rationalise or make light of Kirk’s death on social media, said Deputy Secretary of State Christopher Landau.
“In light of yesterday’s horrific assassination of a leading political figure, I want to underscore that foreigners who glorify violence and hatred are not welcome visitors to our country,” he wrote on X.
Outside events are ‘inherently dangerous’
Yesterday’s event with Kirk was held in an open outdoor courtyard on the Utah Valley University campus.
Many students came straight from class and brought their backpacks, said Sarah Heywood, a 19-year-old student who witnessed the shooting.
There was no bag check or metal detectors, Heywood said, although uniformed police officers were present, along with Kirk’s private security agents.
“An outside event is inherently dangerous,” said Ed Davis, a former Boston police commissioner who runs his own security consultancy.
He noted that in general, private bodyguards are trained to provide protection from nearby threats, not those who may be shooting from far away.
“Frankly, the only people that get that kind of coverage are presidents and heads of state,” Davis said.
After yesterday’s shooting, he added, “we have to start thinking about it”.
Davis suggested that moving high-profile events inside - a more controlled environment from a security standpoint - would be a logical step, although it might not be possible in all situations.
Yesterday’s shooting could also inflame the national debate over whether people should be allowed to carry weapons on college campuses.
State law in Utah changed in May, allowing people aged 18 and older with a concealed-weapon permit to openly carry a gun on campus.
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