Tyler Robinson, the Utah man charged with assassinating Charlie Kirk, was afraid of being shot by police and agreed to surrender as long as it was done peacefully, a sheriff involved with taking him into custody said.

Robinson appeared quiet and sombre when he turned himself in with his parents last Thursday at the Washington County Sheriff's office, a day after Kirk was shot and killed at Utah Valley University, said Sheriff Nate Brooksby.

"He didn't want a big SWAT team at his parent's house or his apartment," said the sheriff, who was only involved with the surrender and not the broader investigation."He was truly fearful about being shot by law enforcement."

On Tuesday, prosecutors charged the 22-year-old Robinson with capital murder and announced they will seek the death penalty while revealing a series of incriminating messages and DNA evidence that they say connect Robinson to the killing of Kirk, a prominent conservative activist and confidant of President Donald Trump.

Utah Valley University students returning to campus Wednesday clustered silently, staring down at the barricaded courtyard where an assassin struck down conservative activist Charlie Kirk in an attack that upended the nation.

Care stations offering stuffed animals, candy and connections to counselling dotted the campus on the first day of classes since the shooting more than a week ago.

Matthew Caldwell, 24, said his classmates were quieter and seemed more genuine about being in class even with sadness still in air.

"The way that we treat each other in our words can ultimately lead to things like this," he said."And I think everybody sort of understands that a little bit better now."

Since the shooting, the Republican president has threatened to crack down on what he calls the"radical left" and classifying some groups as domestic terrorists.

Former Democratic President Barack Obama said this week that Trump has further divided the country rather than work to bring people together.

On Wednesday, the House Oversight Committee called on the chief executives of Discord, Steam, Twitch and Reddit to testify on how they are regulating their platforms to prevent violence.

"Congress has a duty to oversee the online platforms that radicals have used to advance political violence," said GOP Representative James Comer, the committee chair, signalling a shift for congressional Republicans, who had previously scrutinised online platforms for policing free speech.

Hidden note in suspect's apartment

Investigators say that sometime after Robinson fired a single fatal shot from the rooftop of a campus building overlooking where Kirk was speaking on September 10, he texted his romantic partner and said to look under a keyboard.

There was a note,"I had the opportunity to take out Charlie Kirk and I'm going to take it," according to court documents.

After expressing shock, his partner who lived with Robinson in south-western Utah, asked Robinson if he was the shooter. Robinson responded,"I am, I'm sorry."

Utah County Attorney Jeff Gray said DNA on the trigger of the rifle used to kill Kirk matched Robinson, who faced his first hearing in the case Tuesday.

A judge read the charges and said he would appoint an attorney to represent him.

A message was left Wednesday with the county's public defender's office.

Robinson's family has declined to comment to The Associated Press since his arrest.

Investigators looking at whether Robinson had help

Law enforcement officials say they are looking at whether others knew about Robinson's plans or helped, but they have not said if his partner is among those being investigated, only expressing appreciation for the partner sharing information.

The partner apparently never went to law enforcement after receiving the texts. Robinson remained on the run for more than a day until his parents recognised him in a photo released by authorities.

Also getting a closer look is security the day of the attack. Utah Valley is conducting a review, university President Astrid S Tuminez said Wednesday.

Republican Utah Governor Spencer Cox met with students and campus leaders near the shooting scene, saying he understands they might still be haunted and angry over what happened.

"What you do with that anger, that's what determines where we go from here," he said.

Was Charlie Kirk targeted over anti-transgender views?

Authorities have not revealed a clear motive in the shooting, but Gray said that Robinson wrote in a text about Kirk to his partner:"I had enough of his hatred. Some hate can't be negotiated out."

Kirk, a 31-year-old father of two, was credited with energising the Republican youth movement and helping Trump win back the White House in 2024.

His political organisation, Arizona-based Turning Point USA, brought young, evangelical Christians into politics through social media, his podcast and campus events.

While court documents said Robinson wrote in one text that planned the attack for more than a week, authorities have not said what they believe that entailed.

Gray declined to answer whether Robinson targeted Kirk for his anti-transgender views. Kirk was shot while taking a question that touched on mass shootings and transgender people.

Robinson was involved in a romantic relationship with his roommate, who investigators say is transgender.

Parents said their son became more political

Robinson's mother told investigators that their son had turned hard left politically in the last year and became more supportive of gay and transgender rights, Gray said.

She recognised him when authorities released a picture of the suspect and his parents confronted him, at which time Robinson said he wanted to kill himself, Gray said.

The family persuaded him to meet with a family friend who is a retired sheriff's deputy. That person was able to get Robinson to turn himself in, the prosecutor said.

Robinson detailed movements after the shooting

In a text exchange with his partner released by authorities, Robinson wrote about planning to get his rifle from his"drop point," but that the area was "locked down."

The texts, which Robinson later told his partner to delete, did not include timestamps, leaving it unclear how long after the shooting Robinson sent the messages.

"To be honest I had hoped to keep this secret till I died of old age. I am sorry to involve you," Robinson wrote.