The man accused of fatally shooting conservative activist Charlie Kirk has been identified as Tyler Robinson, 22, a Utah native who had been living with his parents "for a long time", authorities said.

Mr Robinson was taken into custody on 12 September after a family member recognised him in surveillance images, a development investigators described as pivotal in ending a nationwide manhunt.

That family member was apparently Mr Robinson's father, who encouraged him to turn himself in, the BBC's US partner CBS News has reported, citing two law enforcement sources. The father then reportedly reached out to a family friend who contacted the sheriff's office.

At a press briefing on Friday announcing the arrest, FBI officials declined to discuss Mr Robinson's background, political leanings, or possible motive, saying the investigation was ongoing.

"We are confident we have the right individual in custody," an FBI spokesperson said, "but we are still working to establish the full picture of who he is and why he acted."