Did we already challenge the option that he placed his backpack (with a rifle inside) behind the AC unit (or another sheltered place close by from where he went on the roof) during one of his earlier visits. Assuming here, the reports about him picking up the rifle and telling his parents he’s off to the shooting range are false or it was another gun he took along there. As it seems the USSS didn’t personaly sweep the building where the gunman was perched. Maybe the locals also didn’t.
