Attendees at the campus event where US conservative activist Charlie Kirk was fatally shot on Wednesday have described mass panic after a shot was heard. Kirk, 31, was killed after he was hit in the neck by a single bullet, which law enforcement believes came from a shooter on the roof of a nearby building. The influencer and close Donald Trump ally had been speaking to about 3,000 people on his American Comeback Tour at Utah Valley University. Videos on social media show Kirk talked about gun violence moments before he was shot. One eyewitness told BBC News: Me and my buddies were having a good time just listening to what was going on and we just saw it, heard a loud shout, loud bang and then I saw his body actually in slow motion kind of fall over. Porter LaFerber, a student at Utah Valley University who described himself as a big fan of Kirk's, was about 50ft away when the incident occurred. I was sitting there filming him, I cut my video and just then I heard this shot, he said. LaFerber recounted hiding behind a cement terrace before fleeing to safety after the immediate danger passed. Other witnesses expressed horror and disbelief at the shooting, some claiming a lack of adequate security measures at the event. The incident raises serious questions about safety at political gatherings and the increasing violence surrounding such events.