Charlie Kirk, a conservative activist and close ally of President Donald Trump who played an influential role in rallying young Republican voters, was shot and killed Wednesday at a Utah college event in what the governor called a political assassination carried out from a rooftop.

“This is a dark day for our state. It’s a tragic day for our nation,” said Utah Gov. Spencer Cox. “I want to be very clear this is a political assassination.”

No suspect was in custody late Wednesday, though authorities were searching for a new person of interest, according to a law enforcement official familiar with the matter who was not authorized to discuss the situation by name and spoke on condition of anonymity. Two people were detained earlier in the day but neither was determined to have had any connection to the shooting and both have been released, Utah public safety officials said.

Authorities did not immediately identify a motive but the circumstances of the shooting drew renewed attention to an escalating threat of political violence in the United States that in the last several years has cut across the ideological spectrum. The assassination drew bipartisan condemnation, but a national reckoning over ways to prevent political grievances from manifesting as deadly violence seemed elusive.

Videos posted to social media from Utah Valley University show Kirk speaking into a handheld microphone while sitting under a white tent emblazoned with the slogans “The American Comeback” and “Prove Me Wrong.” A single shot rings out and Kirk can be seen reaching up with his right hand as a large volume of blood gushes from the left side of his neck. Stunned spectators are heard gasping and screaming before people start to run away. The Associated Press was able to confirm the videos were taken at Sorensen Center courtyard on the Utah Valley University campus.

Kirk was speaking at a debate hosted by his nonprofit political organization. Immediately before the shooting, Kirk was taking questions from an audience member about mass shootings and gun violence.

“Do you know how many transgender Americans have been mass shooters over the last 10 years?” the person asked. Kirk responded, “Too many.”

The questioner followed up: “Do you know how many mass shooters there have been in America over the last 10 years?”

“Counting or not counting gang violence?” Kirk asked.

Then a single shot rang out. The shooter, who Cox pledged would be held accountable in a state with the death penalty, wore dark clothing and fired from a building roof some distance away to the courtyard where the event took place.

Some 3,000 people were in attendance, according to a statement from the Utah Department of Public Safety, which also said the university police department had six officers working the event along with Kirk’s own security detail.

The death was announced on social media by Trump, who praised the 31-year-old Kirk, the co-founder and CEO of the youth organization Turning Point USA, as “Great, and even Legendary.” Later Wednesday, he released a recorded video from the White House in which he called Kirk a “martyr for truth and freedom” and blamed the rhetoric of the “radical left” for the killing.

Utah Valley University said the campus was immediately evacuated and remained closed. Classes were canceled until further notice. Those still on campus were asked to stay in place until police officers could safely escort them off campus. Armed officers walked around the neighborhood bordering the campus, knocking on doors and asking for information on the shooter.

The event, billed as the first stop on Kirk’s “The American Comeback Tour,” had generated a polarizing campus reaction. An online petition calling for university administrators to bar Kirk from appearing received nearly 1,000 signatures. The university issued a statement last week citing First Amendment rights and affirming its “commitment to free speech, intellectual inquiry, and constructive dialogue.”

Last week, Kirk posted on X images of news clips showing his visit was sparking controversy. He wrote, “What’s going on in Utah?”

The shooting drew swift condemnation across the political aisle as Democratic officials joined Trump, who ordered flags lowered to half-staff and issued a presidential proclamation, and Republican allies of Kirk in decrying the violence.

“The attack on Charlie Kirk is disgusting, vile, and reprehensible,” Democratic California Gov. Gavin Newsom, who last March hosted Kirk on his podcast, posted on X.

“The murder of Charlie Kirk breaks my heart. My deepest sympathies are with his wife, two young children, and friends,” said Gabrielle Giffords, the former Democratic congresswoman who was wounded in a 2011 shooting in her Arizona district.

The shooting appeared poised to become part of a spike of political violence that has touched a range of ideologies and representatives of both major parties. The attacks include the assassination of a Minnesota state lawmaker and her husband at their house in June, the firebombing of a Colorado parade to demand Hamas release hostages, and a fire set at the house of Pennsylvania’s governor, who is Jewish, in April. The most notorious of these events is the shooting of Trump during a campaign rally last year.

Former Utah congressman Jason Chaffetz, a Republican who was at Wednesday’s event, said in an interview on Fox News Channel that he heard one shot and saw Kirk go back.

“It seemed like it was a close shot,” Chaffetz said, who seemed shaken as he spoke.

He said there was a light police presence at the event and Kirk had some security but not enough. “Utah is one of the safest places on the planet,” he said. “And so we just don’t have these types of things.”

Turning Point was founded in suburban Chicago in 2012 by Kirk, then 18, and William Montgomery, a tea party activist, to proselytize on college campuses for low taxes and limited government. It was not an immediate success.

But Kirk’s zeal for confronting liberals in academia eventually won over an influential set of conservative financiers.

Despite early misgivings, Turning Point enthusiastically backed Trump after he clinched the GOP nomination in 2016. Kirk served as a personal aide to Donald Trump Jr., the president’s eldest son, during the general election campaign.

Soon, Kirk was a regular presence on cable TV, where he leaned into the culture wars and heaped praise on the then-president. Trump and his son were equally effusive and often spoke at Turning Point conferences.