The man suspected of killing conservative activist Charlie Kirk agreed to turn himself in because he thought it was “inevitable” that he would be caught and feared being shot by law enforcement, Washington County Sheriff Nate Brooksby said Wednesday.

Brooksby, who was involved in the surrender but not the broader investigation, addressed lingering questions about what motivated 22-year-old Tyler Robinson to turn himself in last week, during a press conference with reporters.

“Tyler knew it was just inevitable, with all the law enforcement pressure that he — you know, his picture in the news, the gun on the news — he knew it was inevitable that he would be caught,” Brooksby said. "He was fearful of a SWAT team hit on his house, or he was fearful of being shot by law enforcement."

That concern motivated Robinson to come in voluntarily, he added.

“So, part of the negotiation and getting him to bring himself in was that: That we would treat it as delicate and as soft as possible to make him feel comfortable to where he would show up at my office,” Brooksby continued. “And that's exactly what happened.”

The Utah sheriff reviewed the timeline of the events that transpired last Thursday, a day after Kirk was shot and killed during an event at Utah Valley University. He said he received a call from a former detective who worked for him for many years at 8:02 p.m. The ex-colleague knew the Robinson family through religious association, Brooksby said.

“I couldn't fathom what actually came out of his mouth,” Brooksby said. “So, he said, ‘Hey, I know who Charlie Kirk’s shooter is. I know the family through religious association. And he’s in Washington County now, and we're working on trying to get him to come in voluntarily.’”

The sheriff said the former detective informed him that Robinson was “potentially having some suicidal ideations, was en route to a remote area Washington County.”

“The parents convinced him not to do that,” he continued, “and conveyed that they would stand by him and help him surrender peacefully.”

Within the hour, the suspect and his parents arrived at the sheriff’s office and were greeted by plainclothes officers. Brooksby — who earlier called a sheriff at incident command as soon as he hung up with his former detective — said the alleged gunman waited approximately two-and-a-half hours in a waiting room before lead investigators arrived.

Prosecutors in Utah charged Robinson with capital murder on Tuesday and said they are seeking the death penalty. They also revealed new evidence authorities say connect the suspect to Kirk's assassination.

Over the weekend, Utah Gov. Spencer Cox (R) said Robinson had “not confessed to authorities” and was “not cooperating,” adding, “but all the people around him are cooperating, and I think that’s very important.”