A 22-year-old Utah man who was arrested and booked on murder charges in the assassination 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.

The arrest marked a major break in a case that shocked the country and raised fresh alarms about political violence in a deeply polarized United States.

Tyler Robinson, 22, had become “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.

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 address was still listed as his parent’s home, and he is registered as an unaffiliated voter, according to Utah state records. He does not appear to have a prior criminal record.

The family lives in a suburb of the city of St. George in southern Utah, about a 3.5-hour drive south of the Utah Valley University campus where Kirk was shot.

Family members of Robinson 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 access to the driveway. There was a heavy law enforcement presence, with several police vehicles parked along the street, which was closed at both ends.

There was a heavy police presence outside of the Robinson family’s house on Friday as media arrived. Window coverings were drawn, and a pickup truck was parked in front of the home, blocking access to the driveway.

Officers warned people to stay off the neighbors’ property. Both ends of the street also were blocked, confusing some motorists.

One neighbor, Melissa Tait, said she first noticed the police activity mid-morning Friday.