The conservative American activist Charlie Kirk, a podcast commentator and influential ally of Donald Trump, was shot dead on Wednesday while speaking at Utah Valley University.
The university is located in the city of Orem, about 40 miles south of the Utah state capital Salt Lake City.
About 3,000 people were attending a debate hosted by Kirk’s nonprofit political youth organisation, Turning Point USA, when the shooting happened.
Kirk was addressing the crowd from under a white tent emblazoned with the slogans “The American Comeback” and “Prove Me Wrong”.
At approximately 12.20pm, about 20 minutes after Kirk began speaking, he was shot in the neck. In the preceding moments, he was being questioned by an audience member about gun violence.
Authorities say a lone perpetrator is suspected of firing the single gunshot that struck Kirk. Witness reports and footage recorded before and after the incident appeared to place the shooter on the roof of the Losee Center building, also on the campus about 125 metres away.
In the immediate aftermath of the shooting, footage posted online showed a person apparently moving at pace along the roof of the Losee Center.
Other footage and images showed people taking cover and running from the scene.
Federal, state and local authorities are searching for the shooter, who they said jumped off the roof and fled the campus after the shooting.
On Thursday FBI officials released pictures of a person of interest, though they did not say the person pictured is the suspected gunman. The FBI also said it was analysing a footwear impression, a palm imprint and a forearm imprint.
Photograph: AFP/Getty Images
A high-powered, bolt-action rifle believed to have been used in the attack was recovered from nearby woods.
Two people were detained on Wednesday but neither was determined to be connected to the shooting and both were released.