The suspects in the most recent shooting rampages found it relatively easy to get their guns. The suspect in the shooting at a Boulder, Colorado, supermarket was convicted of assaulting a high school classmate but still got a gun. The man accused of opening fire on three massage businesses in the Atlanta area bought his gun just hours before the attack — no waiting required. They are just the latest suspected U.S. mass shooters to obtain guns because of limited firearms laws, background check lapses or law enforcement’s failure to heed warnings of concerning behavior.