Updated

OREM, Utah — A 22-year-old Utah man who was arrested and booked on murder charges in the killing of Charlie Kirk held deep disdain for the conservative activist's provocative viewpoints and indicated to a family member that he was responsible for the shooting, authorities said Friday.

Tyler Robinson became "more political" in the run-up to the shooting and mentioned during a dinner with family that Kirk would be visiting Utah, Gov. Spencer Cox said at a news conference.

The governor cited as evidence engravings on bullet casings found in the rifle that authorities believe was used in the attack, as well as chat app messages attributed to the suspect that a roommate shared with law enforcement.

The governor credited Robinson's family with helping turn him over to authorities.

President Donald Trump first heralded the arrest on the Fox News show "Fox & Friends."

Robinson is believed to have acted alone, and the investigation is ongoing, Cox said. He was arrested on suspicion of capital murder, weapons and obstruction offenses. He was expected to be formally charged Tuesday ahead of an initial court appearance.

Robinson's arrest late Thursday capped a frenetic day-and-a-half search that just hours earlier seemed stuck when authorities pleaded for tips and leads from the public.

Kirk's widow speaks

On Friday night, Kirk's widow, Erika, delivered her first public remarks since the shooting.

Speaking from the office where her late husband hosted his podcast, she said he loved America, nature and the Chicago Cubs. “But most of all, Charlie loved his children and he loved me with all of his heart.”

Though she did not specifically name Robinson, she had a pointed message for “the evildoers responsible for my husband’s assassination.”

“You have no idea the fire that you have ignited within this wife," she said. "The cries of this widow will echo around the world like a battle cry."

She thanked Trump, saying through tears that her husband loved the president, and vowed to keep her husband's work alive, continuing his campus tour, radio show and podcast.

The killing captivated the public not only because of Kirk's outsized influence in conservative political circles and his close connections with Trump but also because of the pressing questions it raised about the escalating toll of political violence that spanned the ideological spectrum.

"This is our moment: Do we escalate or do we find an off-ramp?" Cox asked, pleading for young people to bridge differences through common ground rather than violence. "It's a choice."

New details 

Authorities have yet to reveal a motive, but they described evidence they said shed potential light on the slaying.

That included the engravings on bullet casings, including one that said, "Hey, fascist! Catch!" Cox said.

In addition, a roommate shared with authorities messages from the chat app Discord that involved a contact named Tyler and discussed a rifle wrapped in a towel, engraved bullets and a scope, the governor said.

A Mauser .30-caliber, bolt-action rifle was found in a towel in a wooded area along the path investigators believe Robinson took after firing a single shot from a distant roof and then fleeing.

The clothes the suspect wore when confronted by law enforcement late Thursday were consistent with what he wore when he arrived on campus a day earlier, and a family member confirmed he drove a gray Dodge Challenger like the one seen in surveillance video that recorded Robinson driving to the university the day of the shooting, Cox said.

Robinson's father recognized him from the photos released by the FBI and told him to turn himself in. Robinson refused at first, but then changed his mind, according to a law enforcement official who spoke on the condition of anonymity. His father reached out for help to their youth pastor, who also occasionally works with the U.S. Marshals and called the agency so he could turn himself in.

Meanwhile, investigators continued to dig into the background of Robinson, who was admitted to Utah State University on a prestigious academic scholarship, according to a video of him reading his acceptance letter posted to a family member's social media account. He attended for only one semester in 2021, a university spokesperson said.

He is enrolled in an electrical apprenticeship program at Dixie Technical College near his hometown, a suburb of St. George in southern Utah.

Robinson is registered as an unaffiliated voter and does not appear to have a prior criminal record. His address was still listed as his parent's home, about a 3.5-hour drive south of the Utah Valley University campus where Kirk was shot.

Robinson's family members did not immediately return messages seeking comment. It was not clear if he had a lawyer.

At his family's home, window coverings were drawn and a pickup truck blocked the driveway. There was a heavy law enforcement presence, with several police vehicles parked along the street, which was closed at both ends.

'He didn't deserve this'

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

He co-founded the nonprofit political organization Turning Point USA, based in Arizona. He was speaking at a campus event on the first stop of his "American Comeback Tour," at the time of Wednesday's shooting.

He was taking questions from an audience member about gun violence when a shot rang out. Kirk reached up with his right hand as blood gushed from his neck.

Trump, who was joined by Democrats in condemning the violence, said he would award Kirk the Presidential Medal of Freedom, the nation's highest civilian honor. Vice President JD Vance and his wife, Usha, visited with Kirk's family Thursday in Salt Lake City and then escorted Kirk's casket to his home state of Arizona aboard Air Force Two.

Tucker and Richer reported from Washington. Associated Press writers Nicholas Riccardi in Denver; Michael Biesecker, Brian Slodysko, Lindsay Whitehurst and Michelle L. Price in Washington; Ty O'Neil in Orem, Utah; Hallie Golden in Seattle; and Meg Kinnard in Chapin, S.C., contributed to this report.