WASHINGTON (CN) - The former Blackwater guard found guilty of murder for the unprovoked firefight that left 14 Iraqis dead in 2007 received a life sentence Monday.
U.S. District Judge Royce Lamberth handed down the sentence for Nicholas Slatten, 31, of Spartan, Tenn.
Slatten was found guilty in October 2014 of murder after a 2 1/2-month-long trial.
Three co-defendants convicted of voluntary manslaughter and firearms violations - Paul Slough, Evan Liberty and Dustin Heard - each got sentences of 30 years and a day.
The Sept. 16, 2007, shooting in Baghdad's Nisour Square killed 14 Iraqis and wounded 20 more.
Prosecutors said the shooting was unprovoked, but the former guards claimed insurgents had attacked their Raven 23 unit.
Slatten was found to have fired the first shots.
The sentences reflected the seriousness of the crimes and the large number of victims, Lamberth said, adding that the U.S. government "should be commended for finding and exposing the truth of what happened in Nisur Square," according to a statement by the Justice Department.
Slough, a 35-year-old of Keller, Texas, was found guilty of 13 counts of voluntary manslaughter, 17 counts of attempted manslaughter, and one firearms offense.
Liberty, a 32-year-old of Rochester, N.H., was found guilty of eight counts of voluntary manslaughter, 12 counts of attempted manslaughter, and one firearms offense.
Heard, a 33-year-old of Maryville, Tenn., was found guilty of six counts of voluntary manslaughter, 11 counts of attempted manslaughter, and one firearms offense.
Jeremy Ridgeway, yet another co-conspirator, has been awaiting sentencing since pleading guilty to manslaughter back in 2008.
Raven 23 had been ordered to evacuate a diplomat from the Izdihar Compound after a bomb exploded nearby, but Commander Jimmy Watson received an order to stand by and not leave the Green Zone upon reaching a checkpoint there.
Watson instead allegedly made a "tactical decision" to move out and secure Nisour Square so that the diplomat would have a safe evacuation route.
The federal jury in Washington, D.C., heard evidence that the four defendants bragged about killing Iraqis, fired their weapons indiscriminately and threw objects at civilians prior to the incident at Nisour Square.
Slatten "made statements that he wanted to kill as many Iraqis as he could as 'payback for 9/11'" and "repeatedly boasted about the number of Iraqis he shot," the government alleged.
Prosecutors also showed that the former Blackwater guards routinely threw water bottles and other items at unarmed civilians, vehicles, wagons and bicycles, without justification, in an attempt to break automobile windows, injure and harass people, and for sport.
The case faced multiple procedural setbacks, leading many to believe the Blackwater guards would not be held accountable for their crime.
U.S. District Judge Ricardo Urbina in Washington, D.C., dismissed the indictment in June 2010 based on prosecutorial misconduct, but the D.C. Circuit reinstated the case in April 2011.
At trial, several Iraqi witnesses testified about witnessing the deaths of their children.
The defendants' colleagues also testified against them. Matthew Murphy, a former Blackwater contractor, said: "I've seen people completely unarmed, people doing nothing wrong, get shot." He added that the Nisour Square shooting was "the most horrible, botching thing I've ever seen in my life."
Last year, U.S. Attorney Ronald Machen called the verdict "a resounding affirmation of the commitment of the American people to the rule of law, even in times of war."
At the sentencing hearing, meanwhile, prosecutor Patrick Martin reportedly emphasized how the defendants "repeated false narratives" and "pointed the fingers at others when they themselves are to blame."
"These men have refused to accept any responsibility for their crimes," Martin said, according to an article from Bloomberg.
Blackwater Worldwide changed its name twice after the corporation became intimately associated with public awareness of wartime crimes, and gross mismanagement of Pentagon resources.
It was renamed Xe Services in 2009, and is now known as Academi.
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