"We are seeking the public's help in identifying this person of interest in connection with the fatal shooting of Charlie Kirk at Utah Valley University. 1-800-CALL-FBI Digital media tips: fbi.gov/UtahValleyShooting"

At a press briefing Thursday morning, authorities said they were able to look back and track a person of interest from their arrival at 11:52 a.m., through a stairwell to the roof and then leaving after the shooting. Evidence collected includes a rifle that was found in a wooded area where the gunman had fled, a palm print, forearm prints and footwear impression: