(NEXSTAR) — Authorities in Utah continue to search for the shooter who killed Charlie Kirk as he spoke at an event on a college campus on Wednesday.

Kirk, 31, was hit by a single gunshot believed to have been fired from the roof of a nearby building. He was rushed to a local hospital in a private vehicle, where he was later pronounced dead, authorities confirmed.

During a Thursday morning press conference, officials with the FBI and the Utah Department of Public Safety said that while two people had been detained in the aftermath of Wednesday’s shooting, both had been cleared by investigators and released.

Investigators, meanwhile, are continuing to try to identify the suspect, who was captured in footage at the event and by doorbell cameras in the neighborhood near Utah Valley University in Orem, roughly 40 miles south of Salt Lake City.

“We do have good video footage of this individual. We are not going to release that at this time,” Utah Department of Public Safety Commissioner Beau Mason said Thursday. He did describe the suspect as someone of “college age” who would have “blended in well” with the crowd.

Mason said the suspect is believed to have arrived near UVU’s campus shortly before noon MT on Wednesday. He did not provide details on how the suspect may have gotten on top of a nearby building. Footage showed a person in black clothing on the roof of the Losee Center, several yards from where Kirk was speaking under a tent.

After the shooting, which happened around 12:20 p.m. MT, Mason explained that the suspect is believed to have run across the rooftop before jumping to the ground and fleeing into a nearby neighborhood.

Those in attendance told Nexstar’s KTVX on Wednesday that security around the event was light, as was typical for Kirk’s events. There were six university police officers assigned to the event, plus some private security. There were no metal detectors or bag checks, students told The Associated Press. Some attendees said no one even checked their tickets.

So far, authorities have recovered a “high-powered bolt-action rifle,” believed to be the weapon used in the shooting, from a wooded area near UVU, as well as impressions of the suspect’s footwear and forearm, and their “palm print,” according to Mason. He went on to briefly indicate that there may be more than one suspect.

“I can’t overstate the tragedy and the horrific event that yesterday was, and how we will work to bring to justice the actions of one individual, or any other individuals that assisted in that,” he said.

Thursday morning, the FBI’s Salt Lake City office released two photos of a person of interest investigators are hoping to identify.

The photos, seen below, show what appears to be a man wearing a ball cap, sunglasses, dark jeans, and a black shirt that seems to feature an American flag and an eagle.

Anyone who may have information about the person pictured above or the shooting are asked to call the FBI at 1-800-CALL-FBI or submit details online.

Authorities have also not yet identified a motive for the shooting.

The attack was captured on grisly videos circulating on social media that show Kirk speaking into a handheld microphone when suddenly a shot rings out. Kirk can be seen reaching up with his right hand as blood gushes from the left side of his neck. Stunned spectators gasp and scream before people start running away.

The FBI is asking anyone who captured video during Kirk’s event to submit it to a dedicated FBI tip portal. Mason, meanwhile, has asked the public “to be patient with the investigative process.”

The Associated Press and Nexstar’s Michael Bartiromo contributed to this report.