DNA evidence links the suspect in the assassination of the conservative American activist Charlie Kirk last week to the scene of the crime, the director of the FBI has said.

DNA from a towel and a screwdriver recovered from the crime scene both match Tyler Robinson, FBI Director Kash Patel said on Monday.

Robinson, 22, was arrested by police on Thursday after a 33-hour manhunt for the killer.

“I can report today that the DNA hits from the towel that was wrapped around the firearm and the DNA on the screwdriver are positively processed for the suspect in custody,” Patel said in an interview on Fox News’s Fox & Friends.

Patel said Robinson had also expressed his desire to “take out” Kirk in a text exchange with another person, and had written a note detailing his plans to commit the crime.

Patel said the note had been destroyed, but investigators recovered forensic evidence of its existence at the home of Robinson and his romantic partner, who prosecutors have said has been cooperating in the investigation.

“We have evidence to show what was in that note, which is… basically saying… ‘I have the opportunity to take out Charlie Kirk, and I’m going to take it’,” he said.

Kirk, the CEO and cofounder of conservative youth activist organisation Turning Point USA and a close ally of US President Donald Trump, was shot dead last Wednesday during a speaking event at a university in Utah.

The killing of Kirk, a polarising figure who was lionised by conservatives and reviled by liberals, has provoked condemnation across the political spectrum, while drawing attention to deep political divisions in the United States and raising fears of further political violence.

The murder has also prompted calls for retribution among the political right, including from Trump, who has promised to use the power of the federal government to crack down on left-wing networks that he claims are driving violence.

On Monday, Trump said his administration was looking into bringing racketeering charges against left-wing groups believed to be funding agitators, and favoured designating the loose-knit antifascist group Antifa as domestic terrorists.

Trump’s pledge to crack down on what he says is left-wing extremism has raised fears that his administration may seek to use Kirk’s murder as a pretext to stifle legitimate dissent.

In an appearance as guest host of Kirk’s podcast, Vice President JD Vance backed a grassroots online campaign to get people who celebrated Kirk’s death fired, urging listeners to “call them out” and “call their employer.”

Numerous employees across the US have been fired or put on leave over their social media commentary about Kirk’s death, not all of whom celebrated or justified the assassination.

Washington Post columnist Karen Attiah said on Monday that she had been fired over her social media posts about Kirk.

In a column on Substack, Attiah said she had been terminated for “speaking out against political violence, racial double standards, and America’s apathy toward guns.”

Attiah included a number of past posts about political violence in her column, only one of which mentioned Kirk specifically.

That posted misquoted Kirk as saying that black women “do not not have the brain processing power to be taken seriously.”

Kirk’s actual comments specifically referred to the intelligence of four black women, including former first lady Michelle Obama and Supreme Court Justice Ketanji Brown Jackson.

Responding to a claim by Vance that “most of the lunatics” in US politics reside on the far-left, Democratic lawmaker Greg Casar accused the Trump administration of weaponising concerns about political violence against its opponents.

“He cannot be allowed to use the horrible murder of Charlie Kirk as a pretext to go after peaceful political opposition,” Casar, who represents a Texas district in the US House of Representatives, said in a statement.

High-profile acts of political violence have targeted figures on both the left and right of US politics in recent years.

They include the killing of a Democratic state lawmaker and her husband in Minnesota in June, two assassination attempts on Trump during the 2024 presidential campaign, and a 2022 hammer attack on the husband of Democratic former House Speaker Nancy Pelosi.

Experts say that politically motivated attacks and threats are on the rise in the US.

More than 250 incidents of threats and harassment against local officials were reported in the first half of 2025, a 9 percent increase from the previous year, according to the Bridging Divides Initiative at Princeton University.

While little information has been released about Robinson’s suspected motive so far, Patel on Monday affirmed an earlier assertion by Utah Governor Spencer Cox that the suspect espoused left-wing views.

“His family has collectively told investigators that he subscribed to left-wing ideology, and even more so in these last couple of years,” Patel said.