Suspect in Charlie Kirk’s assassination in custody, says Donald Trump

"Somebody very close to him turned him in," Trump told Fox News in a live studio interview.

US President Donald Trump on Friday said “with a high degree of certainty” that the suspect in the killing of right-wing activist Charlie Kirk has been taken into custody following a massive manhunt.

Kirk was a "giant of his generation," and a "champion of liberty," Trump said at the beginning of his remarks during a 9/11 ceremony at the Pentagon. (AP)

"I can say with a very high degree of certainty that we have him. Somebody very close to him turned him in," Trump told Fox News in a live studio interview.

Trump said a minister who is also involved with law enforcement turned in the suspect to authorities.

Kirk was shot dead on Wednesday in what police said was a targeted attack, while he was delivering a speech in Utah. The governor there called it a political assassination.

Kirk, a strong Trump ally and a staunch right-wing activist, co-founded the nonprofit political organisation Turning Point USA and was a close ally of Trump.

Authorities recovered a high-powered, bolt-action rifle near the scene and said the shooter jumped off a roof and vanished into the woods after the shooting.

On Thursday, federal investigators and state officials released photos and a video of the person they believe is responsible. Kirk was shot as he spoke to a crowd gathered in a courtyard at Utah Valley University in Orem.

FBI releases suspect's photos

Earlier, the FBI released a series of footage and photos of the suspect, whom they believe is responsible for the shooting of Charlie Kirk on Wednesday, fleeing the scene.

Utah's Department of Public Safety shared four photographs of the suspected gunman.

The suspect is believed to be of college age, wearing a black, full-sleeved T-shirt bearing the American Flag and dark sunglasses, as reported by The Mirror. In addition, he was also wearing the Converse trainers and a baseball cap.