A security expert told Fox News Digital that the rooftop at UVU represented a significant vulnerability. Investigators said surveillance video captured Robinson walking onto the UVU campus shortly before noon on Sept. 10. Video later showed a man climbing a staircase to a common area beside the building, scaling a wall and crouching on the rooftop. After waiting several minutes, he ran across the roof and took a prone shooting position with a direct line of sight to Kirk. CHARLIE KIRK'S KILLING AT UTAH UNIVERSITY PROMPTS SCRUTINY OF SECURITY MEASURES"Many campus police departments do not have drone programs, which is a big problem," he said.