One by one, four former Blackwater security contractors wearing blue jumpsuits and leg irons stood before a federal judge on Monday and spoke publicly for the first time since a deadly 2007 shooting in Iraq. The men had been among several private American security guards who fired into Baghdad’s crowded Nisour Square on Sept. 16, 2007, and last October they were convicted of killing 14 unarmed Iraqis in what prosecutors called a wartime atrocity...[J]udge, Royce C. Lamberth...[sentanced] Mr. Slatten to life in prison and handing 30-year sentences to the three others....The ruling ended a long investigation into the Nisour Square shooting, a signature, gruesome moment in the Iraq war that highlighted America’s reliance on private contractors to maintain security in combat zones...In Iraq, Blackwater was perceived as so powerful that its employees could kill anyone and get away with it, said Mohammed Hafedh Abdulrazzaq Kinani, whose 9-year-old son, Ali, was killed in Nisour Square.