Blackwater Guard's 2nd Murder Trial Ends Without A VerdictEnlarge this image toggle caption Cliff Owen/AP Cliff Owen/APThe second murder trial of Nicholas Slatten, the former Blackwater contractor accused of firing the first shots in a shooting that killed more than a dozen unarmed civilians, has ended in a mistrial. After weeks of deliberations, the jury could not reach a unanimous verdict, and U.S. District Judge Royce Lamberth declared a mistrial on Wednesday. In September 2007, Blackwater guards opened fire on Baghdad's Nisour Square, killing and injuring unarmed civilians. Slatten was convicted of first-degree murder and sentenced to life in prison, while the three other guards were convicted of manslaughter and attempted manslaughter. The resentencing of the other three Blackwater guards had been postponed until after Slatten's case was resolved.