Michael Brandon Hill previously threatened to kill brother
                                
                                
                                    (Newser) -
                                    It could have been a disaster: Police say the  20-year-old arrested  at an Atlanta-area school yesterday with an AK-47 had 500 rounds of ammunition with him, reports  WSB-TV . Though Michael Brandon Hill fired a few shots at police, nobody was injured before his arrest in a school office. It also...