The pictures show a man in sunglasses and a cap whom the FBI is asking for help to identify. He does not mention whether he is suspected of a crime.
The FBI also offers a reward of up to $100,000, equivalent to approximately 930,000 kronor, for information that leads to the identification and arrest of the person or people behind the attack.
Just hours before publication, the FBI and local authorities announced at a press conference that the police had found a gun that they believe was used when Kirk was shot dead during a performance at Utah Valley University on Wednesday.
The gun in question is a repeating rifle and was found in a "wooded area to which the shooter fled". The FBI also says that they estimate that the suspected shooter is in "college age" and that the person should have "melted in" among the students at the university.
We have good video material on this person. However, it is something we will not publish at this time, says a representative for Utah's authorities at the press conference.
"All resources"
From the FBI's side, they do not want to comment on whether they have managed to identify the suspect or if they have secured fingerprints or DNA evidence.
We are using all available means in the work of collecting this, but it is part of the investigation, says Robert Bohls, head of the FBI's office in Utah, at the press conference.
However, it is clear that Charlie Kirk was the target.
I can say that this was a targeted attack, says Robert Bohls.
In addition to the video material, they have also secured shoe prints that are believed to belong to the shooter. How far the suspect may have gotten is unclear, but according to the authorities, they have secured the wooded area where the gun was found.
Shot in front of thousands
Two people were arrested shortly after the fatal shooting but were released after questioning.
Charlie Kirk was sitting comfortably reclined under a tent on a stage at the university campus on Wednesday and discussing mass shootings when he was suddenly shot with a shot. Some of the approximately 3,000 people in the audience threw themselves on the ground. Others fled.
About two hours after the shooting, President Donald Trump announced via social media that Kirk was dead.
The two-child father Kirk is considered to have played a major role in Trump's election victory last year, through his mobilization of young conservative voters. As an 18-year-old, he was involved in founding the conservative student organization Turning Point USA.
