Three private security guards working for Blackwater Worldwide who witnessed a 2007 episode in Baghdad in which at least 17 Iraqi civilians were killed by other Blackwater guards told a federal grand jury that they believed the shootings were unjustified, according to newly unsealed court documents. Two senior United States military officers who arrived at the site soon after the shooting also told investigators that they saw no evidence of insurgent activity that would have justified the shootings, according to the documents. The statements were disclosed in a report prepared by prosecutors in the federal criminal case against five guards from Blackwater, now named Xe Services...