‘We cannot do our job without the public’s help,’ Utah’s governor said, adding the FBI had received more than 7,000 leads and tips so far

US officials have appealed for help from the public for information to help find the shooter, releasing new videos and photos from the scene of the attack at a Utah university.

“We need as much help as we can possibly get,” Utah governor Spencer Cox told a news conference more than 24 hours after Kirk was shot while speaking in front of thousands of people. “We cannot do our job without the public’s help,” Cox said, appearing alongside FBI director Kash Patel – who didn’t speak – and other officials. The FBI had received more than 7,000 leads and tips so far, he said.

Surveillance video newly released by authorities showed a person wearing a hat, sunglasses and a long sleeve black shirt running across a roof, climbing off the edge of the building and dropping to the ground. The suspect is believed to have fled into the local neighbourhood after firing the one shot and has not yet been identified.

Investigators said they had obtained clues, including a palm print, a shoe impression and a high-powered hunting rifle found in a wooded area along the path the shooter fled. But they were yet to name a suspect or cite a motive in the killing. The FBI is offering up to $100,000 for information leading to the identification and arrest of the person.

Donald Trump agreed with a suggestion from a conservative reporter that his supporters should not respond to Kirk’s death with violence, a day after the president blamed the “radical left” for the killing and pledged a wide-ranging response. Trump said Kirk – a close ally – had been “an advocate of nonviolence” and “that’s the way I’d like to see people respond”. He cited “big progress” in the investigation.

Cox pledged to pursue the death penalty once the killer was found, also saying there was “a tremendous amount of disinformation” online.

Kirk’s casket arrived in his home state of Arizona aboard Air Force Two, accompanied by vice-president JD Vance. Vance’s wife, Usha, stepped off the plane with Kirk’s widow, Erika. Vance helped carry Kirk’s casket with a group of uniformed service members as it was loaded on to the plane.

The Oxford Union has “unequivocally” condemned comments apparently made by its president-elect about the fatal shooting of the rightwing activist Charlie Kirk in the US.