US authorities release new video of suspect in Charlie Kirk assassination

US authorities have released a video of a suspect in the assassination of Charlie Kirk, as they raced to find the person responsible for the conservative activist’s killing.

Law enforcement late on Thursday shared footage of the person fleeing the scene after Kirk, 31, was shot dead on a university campus in Utah by an unknown assailant.

The FBI also released several images of an unidentified “person of interest” in the shooting, which they have described as a “targeted” attack.

The FBI asked for public assistance in identifying the individual, who officials described as “college age”. Grainy photographs showed a person wearing a baseball cap, dark sunglasses and a long-sleeved T-shirt emblazoned with images of an American flag and bald eagle.

The agency has offered a $100,000 reward for information leading to the “identification and arrest of the individual(s) responsible for the murder”.

Beau Mason, commissioner of the Utah Department of Public Safety, told MSNBC on Thursday that investigators had “no idea” if the person of interest was close by or still in Utah.

“We cannot do our job without the public’s help right now,” Utah governor Spencer Cox said at a press conference late on Thursday.

Cox said the FBI had received more than 7,000 tips in the case and investigators had conducted more than 200 interviews. “We have people all over the country that are helping to bring this perpetrator to justice for Charlie Kirk and his family.” He added the state was preparing to pursue the death penalty.

Cox, a Republican, was joined by FBI director Kash Patel, who did not make a statement. Neither took questions from reporters.

Earlier on Thursday, law enforcement said they had recovered a “high-powered, bolt action rifle” that they believed was used in the shooting.

The killer’s motive remained unclear. A preliminary internal law enforcement bulletin said ammunition recovered in the investigation bore messages expressing antifascist sentiment and others relating to transgender issues. However, a person familiar with the matter cautioned that such early bulletins may be inaccurate.

Kirk’s murder has shocked a deeply polarised country and prompted calls by some rightwing figures for retribution against what they characterised as inflammatory rhetoric from their political opponents.

“We have a radical left group of lunatics out there, just absolute lunatics, and we’re going to get that problem solved,” US President Donald Trump told reporters on Thursday.

Earlier in the day, at a memorial ceremony for those killed at the Pentagon in the September 11 2001 terrorist attacks, Trump announced that he would posthumously honour Kirk with the presidential medal of freedom, the US’s top civilian honour.

JD Vance, who described Kirk as a “true friend”, helped carry his coffin on to Air Force Two, the vice-president’s official aeroplane, on Thursday evening in Salt Lake City. Kirk’s funeral is expected to be held in Arizona, where he lived. Trump has said he plans to attend.

Kirk was speaking to students at an event on Wednesday at Utah Valley University, a public university in Orem, when he was struck by a bullet in the neck. He was taken to a local hospital, where he was pronounced dead.

His death came amid a period of rising political violence in the US, less than three months after a Minnesota Democratic state lawmaker and her husband were killed in a targeted attack. Pennsylvania’s Democratic governor Josh Shapiro was also the victim of an arson attack and assassination attempt this year.

Trump survived two assassination attempts last summer as he campaigned for the presidency.

Kirk, who was married and had two young children, co-founded Turning Point USA, a grassroots organisation that promotes conservative politics at secondary schools and universities.

The group and its campaign arm, Turning Point Action, rallied support for Trump and the Republican party and were widely credited with galvanising younger voters in recent years.

Kirk also hosted The Charlie Kirk Show, an influential daily talk radio programme. A Turning Point spokesperson last year told NBC News the podcast was being downloaded between 500,000 and 750,000 times a day.

His appearance in Utah was billed as the start of an “American Comeback” tour of college campuses. He regularly drew large crowds for what he described as a “prove me wrong table”, where he engaged in often combative question-and-answer sessions with the audience.

Campus police at Utah Valley University said more than 3,000 people were at Wednesday’s event.