Four Blackwater security contractors sentenced for their part in a 2007 massacre in Baghdad will have their sentences revised, the US Court of Appeals for the District of Columbia Circuit ruled on Friday, while former guard Nicholas Slatten saw his life sentence overturned.

The federal appeals court found that Slatten should have been tried separately from his three co-defendants in 2014. Prosecutors had maintained that Slatten had fired the first shots at a crowded traffic circle in the Iraqi capital, ultimately leading to the deaths of 14 unarmed civilians and a life sentence for his role in the killings.

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However, the appeals court ruled that Slatten should be able to present new evidence at a new trial that one of his colleagues had in fact opened fire.

The federal prosecution's case against Slatten "hinged on his having fired the first shots, his animosity toward the Iraqis having led him to target (their vehicle) unprovoked," the appeals court panel of judges said. However, subsequent statements made by an unnamed co-defendant admitting that that he had fired the first shot "strike at the heart of that theory and instead point to the co-defendant, not Slatten."

Former Blackwater guard Nicholas Slatten was handed a life sentence over the 2007 massacre in Baghdad

New sentences for Blackwater co-defendants

The three other Blackwater contractors involved in the massacre - Paul Slough, Evan Liberty and Dustin Heard - will also receive new sentences. The court on Friday found that their mandatory 30-year sentences had violated the constitutional prohibition of cruel and unusual punishment. Federal prosecutors had charged the men with using military arms while committing another felony - a statute generally employed against gang members or bank robbers, which had never been used against government security contractors.

The court also dismissed Liberty's attempted manslaughter convictions. His attorney, Bill Coffield, said they would review the available options. "Obviously we're pleased with the court's decision in terms of the unconstitutionality of the sentence," he said.

Heard's attorney, David Schertler, said in a statement that his client was entitled to a new trial, writing that "we are gratified that the court recognized the gross injustice of the 30 year mandatory minimum sentences imposed in the unique war zone circumstances of this case."

A spokesman for the US attorney's office said it was still reviewing the decision and no immediate comment.

From left to right: Dustin Heard, Evan Liberty, Nicholas Slatten and Paul Slough

Unanswered questions

The four former Blackwater contractors were sentenced in 2014 following a weeks-long trial in which the prosecution and defense presented contrasting versions of what triggered the slaying.

Federal prosecutors presented the massacre as a one-sided ambush on a group of unarmed civilians, while the defense claimed that the guards only opened fire after a potential car bomb began speeding towards their convoy, which was trying to clear a path for US diplomats. After the shooting, no evidence of a car bomb was ever found.

The incident stood out for its brutality, even as Iraq found itself in the midst of a violent sectarian war. In the US, it sparked fierce debate over the role of private contractors in war zones.

Since the ruling, Blackwater has been sold and is now operating as Virginia-based Academi.

dm/gsw (Reuters, AP)