OREM, United States, Sept 13, 2025 (BSS/AFP) - The widow of prominent right-wing activist Charlie Kirk pledged Friday to carry on her husband's work, after US authorities announced his alleged assassin had finally been captured.

Investigators had appeared to be making slow progress in the hunt for whoever gunned down Donald Trump's close ally, until they released security camera images of a young man.

"We got him," Utah Governor Spencer Cox told a press conference early Friday, identifying the suspect as Tyler Robinson, 22, who had reportedly been confronted by his father over the pictures and then turned in.

The 31-year-old Kirk was hit by a single bullet while addressing a large crowd at Utah Valley University in the town of Orem on Wednesday.

Kirk was an electrifying presence on the US right, with a huge following that helped Trump build the youth vote in his election victory last November.

A heartbroken Erika Kirk on Friday mourned the loss of "the perfect father...the perfect husband."

"The evil-doers responsible for my husband's assassination have no idea what they have done," she said in a live video address.

"You have no idea the fire that you have ignited within this wife; the cries of this widow will echo around the world like a battle cry.

"The movement my husband built will not die. It won't. I refuse to let that happen," she said.

Kirk's murder has consumed America for 48 hours, capturing almost all cable news coverage, while Trump has ordered flags to fly at half-mast.

Kirk's hardline views on race, gender, gun ownership and other hot-button issues made him an intensely divisive figure, although even opponents praised his willingness to debate.

- Bullet markings -

Speculation swirled over markings that Cox said were found on unused bullet casings in the weapon Robinson is believed to have used.

One cartridge had "Hey, fascist! Catch!" written on it, while another featured "Bella ciao," -- a World War II-era Italian anti-fascist song that reports said had recently been repurposed in niche online circles.

Other cartridges were marked with symbols and wording that appeared to be from online gaming culture.

Details about Robinson began to trickle out Friday, as a picture emerged of a young man from a Republican family in a staunchly conservative town.

Photographs showed the young man -- who was in the third-year of an electrician apprenticeship -- posing with guns and dressed for Halloween in a costume in which he appears to be riding Trump's shoulders.

- Breakthrough in manhunt -

Authorities took 33 hours to make the arrest.

In a wooded area near the university, they quickly found the alleged murder weapon, a high-powered hunting rifle, and released photos of a young man dressed in a baseball cap and casual clothing.

However, after detaining, then releasing, two people who turned out to be unconnected to the case, the police and FBI appeared to struggle.

Late Thursday, officials in Orem released more details about the suspect's clothing and initial movements after the shooting, pleading with the public to help identify him.

FBI Director Kash Patel said the arrest was finally made at 10:00 pm Thursday.

Cox credited assistance from the alleged killer's family.

"On the evening of September 11th, a family member of Tyler Robinson reached out to a family friend, who contacted the Washington County sheriff's office with information that Robinson had confessed to them or implied that he had committed the incident," he said.

- Seeking death penalty -

Robinson was being held on suspicion of aggravated murder, and was expected to be formally charged in the coming days.

Utah has the death penalty for such crimes -- a punishment Trump has said he would like to see imposed.

Kirk, whom supporters have hailed as a martyr, co-founded Turning Point USA in 2012 to drive conservative viewpoints among young people, with his natural showmanship making him a go-to spokesman on television networks.

The father-of-two used his audiences on TikTok, Instagram and YouTube to build support for anti-immigration policies, outspoken Christianity and gun ownership, and to spread carefully edited clips of his interactions during debates at his many college events.