A US army prosecutor has said a staff sergeant, accused of killing 16 Afghan villagers, should face a death penalty court-martial.
Prosecutors said 39-year-old Robert Bales left his remote camp in Afghanistan's Kandahar province on two revenge-fuelled forays over a five-hour period in March.
At least nine of the people he is accused of killing were children.
The shootings marked the worst case of civilian slaughter blamed on an individual US soldier since the Vietnam War.
The US government believes Mr Bales was solely responsible for the deaths, and survivors have testified to seeing only a single US soldier.
However, several indirect accounts have suggested that more than one soldier was involved.
A veteran of four combat tours in Iraq and Afghanistan, Mr 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.
He faces the possibility of the death penalty if a military commander decides to hold the court martial as a capital case.
A military jury must later come to a unanimous decision in deciding both guilt and whether to impose the death penalty.
The military justice system also requires the US president to approve the execution of a service member; the last execution in a US military case occurred in 1961.
Prosecutors presented physical evidence to tie Mr 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.
Prosecutors said Mr Bales drank with two fellow soldiers, then left his base and went to a village where he committed the first killings.
He then returned to the camp and had a brief exchange with another soldier before leaving for a second village and killing more people, prosecutors said.