Manhunt underway for Charlie Kirk's shooter.

Police and FBI agents searching for Charlie Kirk's killer say they recovered a bolt-action rifle that may have been used in the fatal shooting. While the suspect's identity has not been announced, the FBI has released images of a person of interest.

Kirk, 31, was a conservative activist and a close political ally of President Donald Trump. He was speaking on an outside courtyard to a crowd of about 3,000 attendees on the campus of Utah Valley University in Orem, Utah, when he was shot and killed by an unknown assailant on Sept. 10.

Law enforcement officials described the attack as targeted, not random. During a news conference on Sept. 11, officials said they found a rifle —believed to have fired the single fatal shot from a nearby rooftop — in a wooded area.

Here is what we know so far about the shooting. All times are local and approximate:

What happened on the day of Kirk shooting?

11:52 a.m.: The shooting suspect arrives on campus, according to Beau Mason, Utah Public Safety Commissioner.

12 noon: Kirk begins speaking.

12:20 p.m.: Kirk is answering questions from the audience when he is shot in the neck. He is rushed to Timpanogos Regional Hospital a few miles from the UVU campus.

12:42 p.m.: UVU issues alert on Kirk shooting. It says a suspect is in custody.

12:53 p.m.: FBI Director Kash Patel confirms Kirk shooting and says the FBI is assisting.

1:10 p.m.: UVU now says a suspect is not in custody.

1:37 p.m.: UVU closes campus.

1:45 p.m.: Kirk is reported in critical condition.

2:40 p.m.: President Trump posts on Truth Social that Kirk has died.

Where was the shooter?

Law enforcement officials say an individual was seen on video jumping from a rooftop and running off campus, USA TODAY reported.

Investigators say they have videos of the suspect entering the campus, going up stairwells, and up to a rooftop location where the shot was fired.

The shooter may have been less than 150 yards from Kirk, according to a USA TODAY analysis of satellite imagery.

Such a short distance is considered well within reach of a basic marksman. Army soldiers, even those in non-combat jobs or those who lack previous firearms experience, must pass a rifle marksmanship test that includes targets as far as 325 yards away after mere days of training.

What gun was used?

The Wall Street Journal and New York Times, citing law-enforcement sources, reported it was an older model Mauser .30-06 caliber bolt action rifle. An ATF spokesperson declined to comment to USA TODAY, citing the active investigation.

The .30-06 round used in the recovered rifle would not experience much, if any, gravitational drop or wind disruption at that distance, either.

In addition to recovering a rifle, investigators have shoe print impressions, palm prints, and forearm imprints for forensic analysis, says Robert Bohls, FBI Special Agent in Charge for the Salt Lake City field office.

Who are police looking for?

Analysis of surveillance videos show the shooting suspect arrived on campus about a half-hour before Kirk started speaking, said Beau Mason, Utah Public Safety Commissioner, in a news conference Thursday morning.

Mason described the suspect as someone who "blended in well" with the campus crowd and was of college age.

Police have traced the suspect's movements off the roof after the shooting before he fled the campus into a neighborhood. Authorities are looking for area doorbell cameras and other security footage.

"We do have good video footage of this individual. We are not going to release that at this time," Mason said. Investigators are using technology to help identify the suspect from the video.

Two people were detained in the hours after the shooting, including one who was interrogated by law enforcement. Both were subsequently released and cleared of being suspects, Mason said.

The shooting, which officials say was a "political assassination," has been condemned by Republicans and Democrats. Trump, who ordered all U.S. flags to be flown at half-staff until sunset on Sunday, has vowed that his administration will "find each and every one of those who contributed to this atrocity."

At around 3 p.m. on Sept 11, a spokesperson for the Utah Department of Public Safety told USA TODAY that the shooter remains at-large and that FBI Director Kash Patel and Deputy Director Dan Bongino are en route to Salt Lake City.

This is a developing story which will be updated.

CONTRIBUTING Melissa Galbraith, Thao Nguyen, Josh Meyer, Jeanine Santucci, Fernando Cervantes Jr., Laura Gersony, Stephanie Murray, N'dea Yancey-Bragg, Joey Garrison, Aysha Bagchi, Dinah Voyles Pulver, Bart Jansen, Swapna Venugopal Ramaswamy, Michael Loria; David Baratz

SOURCE USA TODAY Network reporting and research; Reuters

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This article originally appeared on USA TODAY: Visual timeline of Charlie Kirk shooting and manhunt for shooter

Reporting by Ramon Padilla, Stephen J. Beard, Janet Loehrke, Jennifer Borresen, Will Carless, Davis Winkie, George Petras and Shawn J. Sullivan, USA TODAY / USA TODAY

USA TODAY Network via Reuters Connect