The US is still in shock after the murder of the right-wing activist and Trump friend Charlie Kirk on Wednesday evening Swedish time.

Kirk was shot during a debate at Utah Valley University at 12:20 p.m. in front of thousands of spectators.

He was shot from a distance of just over 180 meters. The shooter was on a roof, where he later fled down towards a residential area.

The FBI has now released a photo of the suspected shooter, who appears to be a young man. The man is wearing a cap, sunglasses and a shirt with an American motif.

“We are asking for the public's help in identifying this person of interest in connection with the shooting death of Charlie Kirk at Utah Valley University”, writes the FBI on social media.

$100,000, just over one million Swedish kronor, is being promised to anyone with information that leads the FBI to identify the person in the photo.

Bullets engraved with “anti-fascist messages”

The weapon believed to have been used in the murder was found in the same residential area in a wooded area.

"We have recovered what we believe is the weapon used in yesterday's shooting. It is a high-powered repeating rifle. The rifle was found in a wooded area where the shooter had fled, so the FBI laboratory will analyze the weapon," Bohls said.

Both CNN and Wall Street Journal reports that investigators found ammunition engraved with anti-fascism and trans rights slogans in the rifle. There were also three unused cartridges in the magazine, all with text on them.

A repeating rifle, or a bolt action rifle, is a type of rifle where the shooter must manually pull back and advance a handle to load a new cartridge into the barrel after each shot.

There are different types of repeating rifles. Some types are used by hunters, while other, more powerful versions are used by military snipers, according to Swedish Hunters' Association.

Sagittarius is of “university age”

Bohls believes that the shooter"blended well into the university environment", and that the shooter is believed to be"of university age".

“We have good video footage of this person,” he says.

Utah police and the FBI initially arrested two people, but both were later released. The people have also faced death threats on social media.

"These people were not suspects, they were persons of interest. We ask that you do not interfere with these people or the investigation process," says Bohls.

Kirk's body will be returned to his family in Arizona.

"The family is devastated. We will not accept what happened yesterday. We are following up on every lead," said Utah Police Chief Beau Mason.