DNA samples taken from two items found near the scene of conservative influencer Charlie Kirk's murder matched the DNA of the suspect in authorities' custody, FBI Director Kash Patel announced Monday.

Five days after this tragedy that struck America and highlighted its political divisions, the investigation is tightening around Tyler Robinson, the 22-year-old man arrested Thursday evening and who is not cooperating with investigators.

Numerous pieces of evidence were collected by the police, "including a screwdriver, which was found on the roof" of the University of Utah campus (west), where the shooter was positioned.

A towel "wrapped around" the sniper rifle was also found at the scene, the head of the FBI, the federal police in charge of the investigation, said Monday on Fox News.

"I can announce today that the DNA from the towel wrapped around the firearm and the DNA on the screwdriver match the suspect currently in custody," said Kash Patel.

Criticized for his actions since the beginning of the case, the FBI chief also mentions a note left by the suspect before carrying out his act.

"The suspect basically wrote, 'I have the opportunity to eliminate Charlie Kirk, and I'm going to take it,'" he said, adding that the FBI had "evidence" of the note, which has since been destroyed.

While Tyler Robinson had "a left-wing ideology," according to the Utah governor, no specific motive has been given for this assassination.

The alleged killer, a high school senior raised in the Mormon faith by Republican parents, is to be formally charged on Tuesday.

The assassination of Charlie Kirk, one of the most popular young influencers on the American right, marks a resurgence of political violence in the United States.

Donald Trump, a close friend of the influencer, confirmed that he would attend a tribute ceremony in Arizona on Sunday in a stadium with more than 63,000 seats.