The D.C. Circuit Court of Appeals ruled Friday afternoon to throw out the first-degree murder conviction of Nicholas Slatten, a former Blackwater Worldwide security guard who played a role in the assassination of 14 unarmed Iraqi civilians in 2007.  The incident sparked international contempt for American military operations in the country, and underscored the deep mistrust between American military personnel stationed in Iraq and the citizens they were there, ostensibly, to protect.

It's not immediately clear whether Slatten, who fired the first shots in the killings, will be retried. Three of his former colleagues who each received 30 years in prison for their roles in the killings—Paul Slough, Dustin Heard, and Evan Liberty—will be re-sentenced.

The court ruled that Slatten's trial should have been held independently from those of his colleagues, arguing that the trial court "abused its discretion" in refusing to do so.