The man accused in the Charlie Kirk assassination had earlier expressed to family his opposition to the viewpoints of the conservative activist, the authorities said Friday in announcing an arrest in a targeted killing that raised fresh alarms about political violence in the United States.

Tyler Robinson, 22, had become “more political” in the run-up to the shooting and had indicated to a family friend afterward that he was responsible, Utah Gov. Spencer Cox said. Cox also cited as key pieces of evidence engravings on bullets found in a rifle believed used in the attack as well as chatting app messages attributed to the shooting suspect that a roommate shared with law enforcement.

Cox, a Republican, called Kirk's killing an “attack on the American experiment,” and he urged a new generation to “choose a different path.”

Robinson is believed to have acted alone, and the investigation is ongoing, Cox said.

Robinson's arrest early Friday morning was disclosed by President Donald Trump, who said in a Fox News Channel interview that, “With a high degree of certainty, we have him.”

Calls to telephone numbers listed for Robinson in public records rang unanswered.

News of the arrest came hours after the FBI and state officials had pleaded for public help by releasing additional photographs of the suspect, a move that seemed to indicate that law enforcement was uncertain of the person's whereabouts.

Kirk was killed by a single shot in what police said was a targeted attack and Utah’s governor called a political assassination. Kirk co-founded the nonprofit political organization Turning Point USA, based in Arizona.

Authorities recovered a high-powered, bolt-action rifle near the scene of the shooting and had said the shooter jumped off a roof and vanished into the nearby woods afterward.

Kirk had been speaking at a debate hosted by Turning Point at Utah Valley University at the time of Wednesday's shooting. He was taken to a local hospital and was pronounced dead hours later.

“He wanted to help young people, and he didn’t deserve this,” Trump said Friday. “He was really a good person.”

Federal investigators and state officials on Thursday had released photos and a video of the person they believe is responsible. Kirk was shot as he spoke to a crowd gathered in a courtyard at the university in Orem.

More than 7,000 leads and tips had poured in, officials said. Authorities have yet to cite a motive in the killing, the latest act of political violence to convulse the United States.

The attack, carried out in broad daylight as Kirk spoke about social issues, was captured on grisly videos that spread on social media.

The videos show Kirk, who was influential in rallying young Republican voters, speaking into a handheld microphone when suddenly a shot rings out. Kirk reaches up with his right hand as blood gushes from the left side of his neck. Stunned spectators gasp and scream before people start running away.

The shooter, who investigators believe blended into the campus crowd because of a college-age appearance, fired one shot from the rooftop, according to authorities. Video released Thursday showed the person then walking through the grass and across the street before disappearing.

“I can tell you this was a targeted event,” said Robert Bohls, the top FBI agent in Salt Lake City.

Trump, who was joined by Democrats in condemning the violence, said he would award Kirk the Presidential Medal of Freedom, the highest civilian honor in the U.S. Vice President JD Vance and his wife, Usha, visited with Kirk's family Thursday in Salt Lake City. Vance posted a remembrance on X chronicling their friendship, dating back to initial messages in 2017, through Vance’s Senate run and the 2024 election.

“So much of the success we’ve had in this administration traces directly to Charlie’s ability to organize and convene,” Vance wrote. “He didn’t just help us win in 2024, he helped us staff the entire government.”

Kirk’s casket was flown aboard Air Force Two from Utah to Phoenix, where his nonprofit political youth organization is based. Trump told reporters he plans to attend Kirk's funeral. Details have not been announced.

Kirk was a conservative provocateur who became a powerful political force among young Republicans and was a fixture on college campuses, where he invited sometimes-vehement debate on social issues.

One such provocative exchange played out immediately before the shooting as Kirk was taking questions from an audience member about gun violence.

The debate hosted by Turning Point at the Sorensen Center on campus was billed as the first stop on Kirk's “American Comeback Tour.”

The event 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?”

Some attendees who bolted after the gunshot rushed into two classrooms full of students. They used tables to barricade the door and to shield themselves in the corners. Someone grabbed an electric pencil sharpener and wrapped the cord tightly around the door handle, then tied the sharpener to a chair leg.

On campus Thursday, the canopy stamped with the slogan Kirk commonly used at his events — “PROVE ME WRONG” — stood, disheveled.

Meanwhile, the shooting continued to draw bipartisan condemnation as Democratic officials joined Trump and other Republican allies of Kirk in decrying the attack, which unfolded during a spike of political violence that has touched a range of ideologies and representatives of both major political parties.