FILE – This June 11, 2014, file photo shows former Blackwater Worldwide guard Nicholas Slatten leaving federal court in Washington after the start of his first-degree murder trial. Slatten and three other Blackwater Worldwide guards are on trial for the killing of 14 Iraqi civilians and the wounding of 18 others in Nisoor Square in Baghdad, bloodshed that inflamed anti-American sentiment around the globe. All four former Blackwater Raven 23 team members have pleaded not guilty. The trial, expected to last months, could feature the largest group of foreign witnesses ever to travel to the U.S. to participate in a criminal trial, according to the Justice Department. (AP Photo/Cliff Owen, File)