Key Points
- US right-wing activist Charlie Kirk was shot and killed during an event in Utah on Thursday.
- Officials said CCTV footage showed an armed individual ascending stairwells to get onto a roof before firing at Kirk.
- The suspect in the shooting has not been identified but investigators have released a grainy image of a person of interest.
Investigators in the United States say they have found a bolt-action rifle they believe was used to kill conservative activist Charlie Kirk and released images of a "person of interest" as they searched for the shooter they described as "college age".
Kirk, a 31-year-old podcast-radio commentator and ally of US President Donald Trump, is credited with helping build the Republican Party's support among younger voters.
He was killed on Thursday AEST by a single gunshot in what Utah governor Spencer Cox called a political assassination.
Federal Bureau of Investigation (FBI) and state officials said the killer arrived on the campus a few minutes before the event began, a talk by Kirk titled Prove Me Wrong outdoors in front of about 3,000 people at Utah Valley University in Orem, Utah, about 65km south of Salt Lake City.
Security-camera videos show an armed individual ascending stairwells to get onto a roof before firing at Kirk, the officials told a news conference.
Kirk, a staunch defender of gun rights, was answering an audience question about mass shootings when the bullet struck his neck, prompting audience members to flee in panic.
The shooter jumped off the roof and fled into an adjoining neighbourhood, Robert Bohls, the FBI special agent in charge, told reporters.
Rifle found nearby as search continues
Investigators found a "high-powered bolt-action" rifle in a nearby wooded area, and were examining that along with palm prints and footprints for clues.
Early Friday AEST, with classes cancelled, the roof of the building on the otherwise deserted campus and the nearby woods were strung with yellow tape as investigators scoured them for evidence.
Right-wing activist Charlie Kirk was killed while speaking at an event at Utah Valley University. Source: Getty / Trent Nelson
The shooter has not been publicly identified, but the FBI circulated grainy images apparently taken from security cameras showing a "person of interest": a person wearing a black top, black sunglasses and a dark baseball cap.
"The FBI is offering a reward of up to [US]$100,000 ($150,000) for information leading to the identification and arrest of the individual(s) responsible for the murder of Charlie Kirk," the bureau said.
Trump said he would posthumously award Kirk with the Presidential Medal of Freedom at a later date.
The medal, the US' highest civilian honour, is awarded by presidents to people who have made significant contributions in a variety of areas, including culture and public service.
— additional reporting by the Associated Press and DPA.
