A federal judge in the United States has dismissed all charges against five security guards from the Blackwater company accused of killing unarmed civilians in Iraq.
The judge said the Justice Department had overstepped its limits and used evidence it was not allowed to.
The guards are accused of killing unarmed civilians in a incident in Baghdad on 16 September, 2007 where they worked as contractors for the US military.
All five had pleaded not guilty to manslaughter. A sixth guard admitted killing at least one Iraqi.
Lawyers for the five say they were acting in self-defence.