The man arrested in the killing of right-wing activist Charlie Kirk in the United States is not cooperating with authorities, but investigators are working to establish a motive for the shooting by talking to his friends and family.
Utah governor Spencer Cox on Sunday said the accused gunman, Tyler Robinson, 22, would be formally charged on Tuesday. He remains in custody in Utah.
Investigators have yet to piece together why Robinson allegedly scaled a rooftop at Utah Valley University during an outdoor event and shot Kirk in the neck at long range on Wednesday last week.
Kirk, a staunch ally of US President Donald Trump and co-founder of the conservative student group Turning Point USA, was killed by a single rifle shot during the event attended by 3,000 people in Orem, about 40km south of Salt Lake City.
Charlie Kirk was killed by a single shot from a rifle while speaking at an event at Utah Valley University. Source: Getty / Trent Nelson/The Salt Lake Tribune
Robinson has not confessed to investigators, Cox told the ABC in the US.
"He is not cooperating, but all the people around him were cooperating, and I think that's very important," the Republican governor said.
Cox said that Robinson's roommate, who was also a romantic partner, had been "incredibly cooperative" with authorities, citing the Federal Bureau of Investigation.
Robinson, a third-year student in the electrical apprenticeship program at Dixie Technical College, part of Utah's public university system, was taken into custody at his parents' house, about 420km southwest of the crime scene after a 33-hour manhunt.
Relatives and a family friend alerted authorities that he had implicated himself in the crime, Cox said previously.
While Robinson was raised by religious parents in a deeply conservative region of the state, "his ideology was very different than his family," Cox said on Sunday on an NBC program.
State records show Robinson was a registered voter but not affiliated with any political party.
A relative told investigators that Robinson had grown more political in recent years and had once discussed with another family member their dislike for Kirk and his viewpoints, according to the arrest warrant affidavit.
Robinson was "not a fan" of Kirk, Cox said on Sunday.
Investigators found messages engraved into four bullet casings, which included references to memes and video game in-jokes.
An affidavit filed by authorities in the case described these messages.
