The shooting rampage at Trolley Square was not Sulejman Talovic's first act of violence. At age 12, Talovic was before a judge for allegedly holding a knife over the head of girl while stating, "I'll kill you," according to a source who is familiar with the case. Two years earlier, Talovic was referred to juvenile court for throwing rocks at a little girl. About the same time, he threatened his parents' landlord with a knife. The first girl was not struck by the stones. And the mother of the second girl snatched her up in the nick of time, just...