WASHINGTON — The United States government’s decade-long attempt to prosecute four Blackwater contractors in the shooting of dozens of unarmed Iraqis in 2007, a case that became a symbol of American power run amok during the Iraq war, was dealt a blow on Wednesday when the retrial of one security guard ended in a hung jury. The retrial of the former Blackwater contractor, Nicholas A. Slatten, was declared a mistrial by Judge Royce C. Lamberth of the Federal District Court for the District of Columbia after jurors deliberated for 16 days without reaching a verdict. The deadlocked jury was the latest twist in the government’s saga to hold people to account for the shooting in Baghdad’s Nisour Square, in which at least 31 people were killed or wounded when contractors in armored trucks began firing machine guns and launching grenades into a busy traffic circle. While escorting a diplomatic convoy on September 16, 2007, they opened fire with sniper rifles, machine guns and grenade launchers, allegedly without provocation, in the bustling square, leaving at least 14 civilians dead and at least 17 wounded. 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 team was part of a convoy protecting State Department personnel,

But a federal appeals court last August ordered a new trial for Slatten, saying he should have been tried separately from a co-defendant, Paul A. Slough, 38, who told investigators days after the shootings that he, not Slatten, fired the first rounds in the incident.
The second trial of U.S. citizen Nicholas Slatten, the former Blackwater (now Academi) employee who was found guilty in 2013 of first-degree murder in connection to the killing in 2007 of fourteen unarmed civilians on Baghdad's Nisour Square and sentenced to life in prison, ends in a mistrial.