Suspected Colorado gunman James Holmes was incredibly well-armed. In the past 60 days, reports ABC, he had purchased four guns at local shops and over 6,000 rounds of ammunition online. According to Aurora Police Chief Dan Oates, "All the ammunition he possessed, he possessed legally, all the weapons he possessed, he possessed legally, all the clips he possessed, he possessed legally." The weapons used in the theater shooting Friday were powerful enough to penetrate the walls, hitting at least one other person in an adjacent theater. Holmes was arrested shortly after the violence, while shooting at his car from behind the theater. Authorities haven't identified all of the 12 victims, while 30 remain hospitalized. Counting the injured, the Friday morning attack is the largest mass shooting in American history. "The gunmen never had to reload. Shots just kept going, kept going, kept going," a witness told ABC News.