 The FBI's priority is getting into this man's phone to see what is inside. We're talking about 20-year-old Thomas Crooks. The official motive is still unknown, but we're told this was a lone wolf attack. The 20-year-old lived in Bethel Park, south of Pittsburgh. Investigators spent the majority of the day at his home, also looking through a van where Fox News has told authorities found explosive devices. At his home, investigators say they found bomb-making materials.