Warning: This story contains details of alleged child sexual abuse.
A 71-year-old man arrested and released shortly after Charlie Kirk's killing has admitted to yelling that he was the shooter in order to "allow the actual suspect to flee", according to US police.
Utah County Sheriff Michael Smith said George Zinn was being held on obstruction of justice charges over the incident.
Officers have separately charged him with possession of child sex abuse material.
"At this time, there is no information that George Zinn actually colluded with the shooter," the sheriff said in a statement.
Prime shooting suspect Tyler Robinson, 22, appeared to refer to Mr Zinn's initial arrest in a text exchange with his roommate in which he said police had "grabbed some crazy old dude".
Sheriff Smith said people were fleeing the Utah Valley University campus after Mr Kirk was shot there on September 10 when Mr Zinn was seen shouting that he had shot the conservative activist.
Authorities revealed on Monday, local time, that Mr Zinn had yelled "I shot him, now shoot me".
University police arrested Mr Zinn and transported him to the police department, according to the sheriff.
"Zinn was not cooperative with Law Enforcement and did not want to speak with Investigators," the statement said.
The 71-year-old was subsequently transported to a local hospital after he began to have a "medical issue".
Police said that while he was there he "freely" stated that he was not the shooter and had made the false claims to hinder officers' response and "allow the suspect to flee".
Police say child abuse material found on Zinn's phone
During the interview, Mr Zinn also allowed investigators from the FBI and Utah State Bureau of Investigation to examine his phone.
However, he warned agents that he used his phone to "view and abuse" child sexual abuse material.
"Those Agents did see several images on the phone of prepubescent girls scantily dressed," the sheriff's office statement said.
On September 15, Utah investigators obtained a search warrant for Mr Zinn's phone, on which they viewed more than 20 images of children in various stages of undress and sexual posing.
Sheriff Smith said the investigation into the child sexual abuse material was ongoing.
Shooting suspect Mr Robinson appeared in court on Tuesday, local time, after being formally charged over Mr Kirk's assassination.
He is facing charges including aggravated murder, committing a violence offence in the presence of a child, discharging a firearm causing a serious bodily injury, obstruction of justice and tampering with a witness.
