A source familiar with the investigation into Turning Point USA Founder Charlie Kirk’s assassination told Fox News Digital that the FBI is investigating leftist groups in Utah to see if they had any connection to the alleged shooter.

Kirk was assassinated during an event hosted by TPUSA on Sept. 10 at Utah Valley University in Orem, Utah. He was taken to a local hospital in critical condition following the shooting, where he later died, officials said. 22-year-old Tyler Robinson has been named as a suspect in the assassination.

The source told Fox News Digital that the FBI is investigating the leftist groups to see if they knew about the alleged shooter’s plans beforehand or provided any assistance to him. The source did not elaborate on which groups are being investigated.

Tyler Robinson, 22, is suspected of shooting and killing Charlie Kirk. (Utah Gov. Spencer Cox)

Authorities said Sunday that Robinson is being held under “special watch” pending the completion of a mental health evaluation.

Until Robinson clears a mental health evaluation, authorities are keeping a “close eye” on him, the Utah County Sheriff’s Department said in a statement.

Map shows Orem, Utah, where the Kirk assassination took place, and St. George, Utah, where the suspect was taken into custody on September 12, 2025. (Fox News)

After Robinson is cleared, he’ll go through the classification process used to determine where those in custody are housed.

“He will continue to be monitored by mental, medical, and custody staff throughout the duration of his stay,” the statement continued.