The man arrested in the killing of right-wing activist Charlie Kirk is not cooperating with authorities, with investigators instead turning to his friends and family to piece together the motivation for the shooting, Utah’s Governor has revealed.
Spencer Cox said the accused gunman, Tyler Robinson, 22, would be formally charged on Tuesday. He remains in custody in Utah.
Investigators are yet to understand why Robinson allegedly scaled a rooftop at Utah Valley University and shot Kirk in the neck at long range on Wednesday.
The staunch ally of President Donald Trump and co-founder of the conservative student group Turning Point USA was killed by a single rifle shot during the outdoor event attended by 3,000 people.
The father of two’s killing ushered in newfound fears of a spike in political violence in the United States and an ever-deepening divide between the left and the right.
Robinson has not confessed to investigators, Mr Cox told the ABC programme "This Week."
"He is not cooperating, but all the people around him were cooperating, and I think that's very important," the Republican governor said.
One person who is apparently talking to investigators is Robinson's roommate, who was also a romantic partner, Mr Cox said, citing the FBI.
Mr Cox described the roommate as "a male transitioning to female," and said the roommate has been "incredibly cooperative."
Asked on CNN's "State of the Union" programme whether the roommate's gender identity is relevant to the investigation, Mr Cox said, "That's what we're trying to figure out right now. ... It's easy to draw conclusions from that, and so we've got the shell casings, other forensic evidence that is coming in - and trying to piece all of those things together."
Investigators found messages engraved into four bullet casings, which included references to memes and video game in-jokes.
One of the inscriptions read: "hey fascist! CATCH!" followed by a combination of directional arrows, an apparent reference to a sequence of button presses that unleashes a bomb in a popular video game.
Another casing read, "If you read This, you are GAY Lmao". Kirk's charged rhetoric, which often involved anti-LGBT and anti-immigrant comments, attracted legions of conservatives, but also engendered strong feelings from liberals and drew widespread criticism.
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 260 miles 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, Mr 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," Mr Cox said on Sunday on NBC's "Meet the Press" programme, without going into specifics.
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.
The killing has stirred outrage among Kirk's supporters and condemnation of political violence from some across the ideological spectrum.
Many Republicans, including Mr Trump, have been quick to lash out at the political left, accusing liberals of fomenting anti-conservative criticism that would encourage a kindred spirit to cross the line into violence - even as the president and his allies have often invoked violent imagery against their opponents.
Mike Johnson, the Republican speaker of the U.S. House of Representatives, urged calm on Sunday.
On "Meet the Press," Mr Cox assigned some blame to social media, saying it has "played a direct role in every single assassination and assassination attempt that we have seen over the last five, six years."
Mr Trump has credited Kirk with driving young voters to conservatism. His Turning Point movement says it has more than 800 chapters across college campuses. Kirk's widow on Friday said the movement's efforts would go forward.
A memorial event for Kirk will be held on September 21 in Glendale, Arizona, his organisation said.
It comes after hundreds of people attended a vigil for Charlie Kirk in central London where speakers hailed him as a “Christian martyr” and called for people to wage a “war on evil”.
