In a move likely to cause a new round of controversy as well as resentment within Iraq, the US Court of Appeals today threw out the lone first-degree murder conviction related to the 2007 Nisour Square Massacre, and also overturned the sentences of other former Blackwater mercenaries involved, who had been convicted of manslaughter.

The Nisour Square massacre of September 16 of 2007 was a major turning point in the Iraqi public’s view of the US occupation, and led to an outright ban on the use of US military contractors by the Iraqi government. During the incident, Blackwater employees attacked and killed 14 Iraqi civilians, and wounded 17 others.

Nicholas Slatten was convicted of first-degree murder over the massacre, with court documents showing he bragged about the killings being a “payback for 9/11.” The Appeals Court says he should have been tried separately from the other three Blackwater employees.

Those three, Paul Slough, Evan Liberty, and Dustin Heard, got lesser sentences for manslaughter and attempted manslaughter on the grounds that Slatten fired first and they simply joined in. The court, however, insists the sentences for these three amount for spraying gunfire and throwing grenades into a crowd of civilians amounts to unconstitutional “cruel and unusual punishment,” with one of the judges saying it was “poor judgement” that led to the massacre.