 ABC's Aaron Katursky reports law enforcement found items of concern in the shooter's car. They're trying to determine if those are explosives. The investigation into his background and motive continues. This 20-year-old young man, a local man from here in western Pennsylvania, we know the authorities have already searched locations associated with him, interviewed members of his family and friends. They're looking for anything online that might give them a hint about motive. So far, they believe he acted alone and that there