Chaos broke out at Utah Valley University when prominent right-wing influencer Charlie Kirk was shot dead in front of thousands of people.
Mr Kirk, 31, was speaking to students about mass shootings on Wednesday when he was shot in the neck, leading students to flee and a manhunt for the killer beginning.
Many questions remain, with differing accounts and multiple videos across social media.
The Sky News Data and Forensic team has tracked and mapped the events before, during and after the killing to find out as much as possible about what happened.
When and where did the shooting happen?
Mr Kirk was speaking to around 3,000 people from under a small white tent on the campus when he was shot.
The event was part of his "prove me wrong" series, which saw the right-wing influencer visit campuses across the country and debate contentious subjects like gun control, free speech, LGBTQ+ rights and abortion rights with left-wing students.
The event began at roughly 12pm local time.
Mr Kirk was taking questions about mass shootings and gun violence when, at roughly 12.20pm, he was shot.
It was a single shot that struck him in the neck, a university spokesman confirmed.
Madison Lattin, who was standing only a few dozen feet to the left of Mr Kirk when he was shot, said: "Blood is falling and dripping down, and you're just like so scared, not just for him but your own safety."
Footage from the scene showed Mr Kirk being carried away within seconds of the shooting.
Where did the shot come from?
In a statement on Thursday, the FBI said they had tracked the gunman's movements onto the campus, "through the stairwells, up to the roof, across the roof, to a shooting location".
They said they first tracked his movements from 11.52am, when they said he arrived on campus.
Videos from the event show the gunman was on top of the Losee Centre building - just over 130m away from where Kirk was speaking, according to an online measuring tool.
Two videos show a figure on the roof before and immediately after a shot is fired.
The first video shows what appears to be someone lying down. The person filming says "he just ran from over there" - pointing in the direction of a stairwell coming up the roof.
The second video is filmed in the moments after the shot is fired. You see a silhouette that appears to stand and move away from the roof's edge.
Using videos taken near the stage, Sky News was able to confirm that this position has a direct line of sight to where Kirk was sitting at the time of the attack.
Audio analyst Rob Maher has estimated the distance the shot travelled, reaching a similar conclusion to Sky News' analysis.
"The time gap between the crack sound and the pop sound in the recordings close to the podium is about 240 milliseconds," he told Sky News.
"Since the exact trajectory of the bullet and the bullet's speed is not known, I have to make an assumption that the bullet speed was likely about 800 meters per second. With that assumption, the time gap indicates that the firearm was likely about 140m from the podium".
What weapon was used?
The weapon suspected of being used in the shooting has been found, according to FBI agent Robert Bohls, who told a news briefing in Orem, Utah, that it was a "high-powered, bolt-action rifle".
"That rifle was recovered in a wooded area where the shooter had fled," he said. "The FBI laboratory will be analysing this weapon."
Mr Bohls added that they also found an "impression of a palm print and forearm imprints for analysis"; however the shooter remained at large.
Firearms consultant David Dyson told Sky News that, based on the range from where they are believed to have fired, the gunman would likely need to be a somewhat skilled target shooter.
But he suggested that while the shot may be difficult for anyone without experience, it's "not a great range" for someone with practice.
"There's target disciplines, for instance, [at] 800m. So you can shoot quite accurately at far greater distances than 150 yards," he said.
"If we're in that sort of ballpark, then you're not looking at somebody with phenomenal skill," he added.
What do we know about the shooter?
A manhunt is under way for the killer, which began on the university campus but has now extended beyond.
Police radio recordings show the first mention of the incident at 12.26pm, about six minutes after the shooting occurred.
Officers were on the scene within minutes, with one officer describing the suspect at 12.35pm as "wearing jeans, black shirt, black mask, long rifle".
By 12.58pm, 32 mins after the shooting, armed officers could be seen checking the perimeter of the Losee building.
In an update on Thursday, authorities offered a few more details about the shooter, who they referred to as a male.
Beau Mason, commissioner of the Department of Public Safety, said he "appears to be of college age" and that he "blended in well with a college institution".
The authorities added they were "doing everything we can to find him" but that "we're not sure how far he has gone yet".
The FBI later released images of a "person of interest" in the shooting.
Two people were arrested after the shooting, but neither was determined to have any connection with the shooting and were later released.
What sort of security was on site?
Witnesses have spoken about a supposed lack of security checkpoints, with people being able to walk into the event with backpacks without being searched.
"Anybody in the world could park anywhere around the university and walk right in," one witness told Sky News affiliate NBC news.
Read more:
Who was Charlie Kirk? The young MAGA influencer 'admired' by Trump
Killing of MAGA icon could be a moment of jeopardy for America
The UVU website states that "generally, anyone is allowed to enter areas that are open to the public" but non-public areas are restricted by "access cards, locked doors, or monitored entryways".
A 2012 drone video shows the area around the shooter's location on the 4th floor. A metal railing encloses an accessible balcony area which means that to reach the roof where the shot was taken, they could have climbed or jumped over the railing.
Extra security measures were put in place for the event. UVU Police Chief Jeff Long said six police officers were there as well as plainclothes police officers in the crowd.
Chief Long confirmed that Mr Kirk also had a security team, which travels with him, and said he coordinated with Mr Kirk's lead security officer.
Analysis of the videos from the event show at least four men, who appear to be Kirk's security team, surrounding the stage.
"We train for these things, and you think you have these things covered," Chief Jeff Long said in his statement last night.
"You try to get your bases covered and unfortunately today we didn't".
The Data and Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling we aim to better explain the world while also showing how our journalism is done.
(c) Sky News 2025: What we know about how Charlie Kirk was killed