The breaking news was announced by US President Donald Trump on a morning television show.
"I think with a high degree of certainty, we have him," said Trump on the sofa of Fox & Friends on Friday morning in New York City. "In custody."
"Essentially, someone that was very close to him turned him in."
It was Trump, too, who first announced that his ally, Kirk, had died after he was shot in the neck at Utah Valley University on Wednesday.
At a press conference on Friday morning, officials identified the person in custody as 22-year-old Tyler Robinson.
