* Wife of victim told investigator more than one soldier was present
* Survivors have testified to seeing only a single soldier
* Teenage boy who survived says shooter wore U.S. military uniform
The wife of an Afghan villager killed in a rampage blamed on a decorated U.S. officer told an Army investigator that more than one soldier was present when her husband was shot dead at their home in March, the investigator testified on Saturday.
Military prosecutors are seeking the death penalty for Army Staff Sergeant Robert Bales, accusing him of killing 16 villagers, mostly women and children, when he ventured out of his remote camp on two revenge-fueled forays over a five-hour period in March.
The wife's account, relayed by Army criminal investigator Leona Mansapit, appeared to cast doubt on the government's case that Bales alone was responsible for the deaths, although survivors have so far testified to seeing only a single soldier.
The U.S. government, which has been laying out its case against Bales in a pre-trial hearing aimed at deciding whether he can be sent for court martial, says a coherent and lucid Bales acted alone and with "chilling premeditation".
Mansapit said that the wife of Mohamed Dawood, who was killed in the village of Najiban, recalled a gunman entering the couple's room shouting about the Taliban, while another man, a U.S. soldier, stood at the door.
The shootings in Afghanistan's Kandahar province marked the worst case of civilian slaughter blamed on an individual U.S. soldier since the Vietnam War and damaged already strained U.S.-Afghan relations.
Mansapit said the wife, who spoke to her through an interpreter, said one of the men pulled her husband out of the door, while the other stopped her from following. One of the men then put a gun to her husband's head and killed him, while the other continued to yell about the Taliban, grabbing her by the hair and slamming her head against the wall, she said.
Mansapit, who was called by the defense, recalled the woman as saying that outside there were more soldiers "speaking English among themselves". She put the woman's age at about 25 but did not name her. It was not immediately clear whether the wife would testify to the hearing herself.
The testimony came a day after a father and two sons described being attacked by a sole U.S. soldier in their family compound in the Afghan village of Alkozai. So far, the only sworn references to more than one soldier have been second hand.
A veteran of four combat tours in Iraq and Afghanistan, Bales faces 16 counts of premeditated murder and six counts of attempted murder, as well as charges of assault and wrongfully possessing and using steroids and alcohol while deployed.
Prosecutors have already presented physical evidence to tie Bales to the crime scene, with a forensic investigator saying a sample of blood on his clothing matched a swab taken in one of the compounds where the shooting occurred..
Bales' lawyers have not set out an alternative theory to the prosecution's case, but have pointed out inconsistencies in testimony and highlighted incidents before the shooting where Bales lost his temper easily, possibly setting up an argument that he was suffering from post-traumatic stress disorder.
Gathering evidence and witness statements was complicated by the speedy burial of victims, the inability of U.S. investigators to access the crime scenes for three weeks after the violence, and the dispersal of possible witnesses after treatment at a Kandahar hospital.
Bales' lead civil defense attorney John Henry Browne, who is in Kandahar to question witnesses, complained early in the investigation that his team was denied access to villagers wounded in the attacks.
One of the villagers, a 15-year-old boy who was wounded in the rampage in Alkozai but survived by hiding, testified to the hearing at a U.S. Army base in Washington state that the shooter wore a U.S. military uniform.
"He put his pistol in my sister's mouth and then my grandmother started wrestling with him," the boy, introduced to the court by the single name of Rafiullah, said via video link from Kandahar Air Field. "He shot me in my legs."
The boy's testimony was consistent with the recollections of another teenage boy, Sadiquallah, who testified previously that he saw only a single American that night.