A Marine sergeant who led a squad that killed 24 unarmed Iraqis avoided serving any time Tuesday for his role in one of the darkest chapters of the Iraq war, winning leniency through a plea deal that carried no real punishment beyond a reduction in rank.

Military Judge Lt. Col. David Jones said he did not realize until after he recommended that Staff Sgt. Frank Wuterich serve three months in the brig that his hands were tied by the deal that prevented any jail time.