Jeremy Ridgeway's testimony undercuts the defense of four former Blackwater colleagues, who claim they acted in self-defense because they believed they were under attack by insurgents. Ridgeway is the prosecution's key cooperating witness in the criminal trial, which has been under way for the past month and a half.

Ridgeway told a jury Thursday that he didn't see any Iraqis pointing guns in Nisoor Square, that there were no telltale muzzle flashes in the distance, that there was no incoming fire and that there was no sound of AK-47 rounds going off, as would be the case if insurgents were shooting at the Blackwater guards from nearby.

Ridgeway said that after some of the Blackwater guards opened fire, most of the Iraqis in the area were fleeing for their lives, running away from, rather than toward, the Blackwater convoy of four heavily armed vehicles.

Defense lawyers will seek to discredit Ridgeway's testimony.

Ridgeway has pleaded guilty to voluntary manslaughter and attempted manslaughter. Three of his former colleagues are charged with voluntary manslaughter, attempted manslaughter and gun violations that would send them to prison for a mandatory minimum sentence of 30 years if convicted. A fourth Blackwater guard, Nicholas Slatten, is charged with first-degree murder.

They are charged in the deaths of 14 Iraqis in the shooting.

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