 He's not detained. He's not questioned by any security. Then 30 minutes later, 530, 40 minutes before the shooting, Crooks is actually photographed by security crawling around like a little smiegel man on top of the freaking ground before he gets on top of the roof. Again, at 530, they did not detain him. Now, fast forward a few minutes before the shooting, Crooks climbs on top of that building where law enforcement are staged.