Charlie Kirk was killed by a single shot from a rifle while speaking at an event at Utah Valley University. Source: Getty / Trent Nelson/The Salt Lake Tribune

The killing ushered in newfound fears of a spike in political violence in the US and an ever-deepening divide between the left and the right.

“He is not cooperating, but all the people around him were cooperating, and I think that’s very important,” the Republican governor said.

Robinson, a third-year student in the electrical apprenticeship program at Dixie Technical College, part of Utah’s public university system, was taken into custody at his parents’ house, about 420km southwest of the crime scene after a 33-hour manhunt.

State records show Robinson was a registered voter but not affiliated with any political party.