A US marine is to go on trial over the killing of 24 men, women and children in the Iraqi town of Haditha in 2005.
The trial of Staff Sgt Frank Wuterich will go ahead after a military judge in California refused to dismiss the charges.
Sgt Wuterich is one of eight marines originally charged with murder or failure to investigate the killings.
The charges against six of them were dropped or dismissed, and one was acquitted.
Lawyers for Sgt Wuterich had argued that his case should be dismissed.
They said that an investigator into the incident was involved in meetings with the general who brought the initial charges against the soldiers.
But the judge ruled that there was no unlawful influence and no record of any "meaningful comment" between the general and an aide who had investigated the case as a military lawyer.
It means Sgt Wuterich faces a trial on charges of voluntary manslaughter and other crimes connected to the attack in Haditha.
The deaths occurred after a marine was killed by a roadside bomb.
Sgt Wuterich and a squad member were accused of shooting five men by a car at the scene.
Investigators say he then ordered his men to clear several houses with grenades and gunfire.
At an earlier hearing, Sgt Wuterich said he regretted the loss of civilian lives but believed he was operating within military combat rules when he ordered his men to attack.