A federal jury has returned guilty verdicts for all four former Blackwater security guards charged in the 2007 shootings of more than 30 Iraqis in Baghdad.The jury in Washington found Nicholas Slatten guilty of first-degree murder.The three other three guards - Paul Slough, Evan Liberty and Dustin Heard - were found guilty of voluntary manslaughter.The four men were charged with a combined 33 counts in the shootings.The jury had reached verdicts on only part of the charges, but Judge Royce Lamberth allowed them to announce the verdicts on Wednesday that they had reached.The jury is expected to continue deliberating on the other counts.