 Just hours before shots were fired at a campaign rally in Butler, Pennsylvania, we are now learning the 20-year-old gunman purchased 50 rounds of ammunition at a local gun store, according to a senior law enforcement official. The AR-style weapon used by Thomas Matthew Crooks now being traced back to his father. While the FBI is working to determine a motive behind the attack that left one man dead and two others critically wounded, former classmates of Crooks describe him as quiet.