The US Army is to seek the death penalty for the soldier accused of killing 16 Afghan villagers in a pre-dawn rampage.
The announcement follows a pre-trial hearing for Staff Sgt Robert Bales (39), who faces premeditated murder and other charges over the attack on two villages in southern Afghanistan in March.
The killings drew such angry protests that the US temporarily halted combat operations in Afghanistan and it was three weeks before American investigators could reach the crime scenes.
Prosecutors said Sgt Bales left his remote southern Afghanistan base early on March 11, attacked one village and returned to the base, then left again to attack another. Of the 16 people killed, nine were children.
No date has been set for Sgt Bales's court-martial, which will be held at Joint Base Lewis-McChord, Washington.
His civilian lawyer, John Browne, said he met army officials last week to argue that his client should not face the possibility of the death penalty, given that Sgt Bales was on his fourth deployment.
"The army is not taking responsibility for Sgt Bales and other soldiers that the army knowingly sends into combat situations with diagnosed PTSD (post-traumatic stress disorder), concussive head injuries and other injuries," Mr Browne said.
"The army is trying to take the focus off the failure of its decisions and the failure of the war itself, and making Sgt Bales out to be a rogue soldier."
Sgt Bales's defence team has said the US government's case is incomplete.
Outside experts have said that a key issue going forward will be to determine if he suffered from post-traumatic stress disorder.
During last month's preliminary hearing, prosecutors built a strong eyewitness case. One soldier said Sgt Bales woke him up, saying he had just shot people at one village and that he was heading out again to attack another. The soldier said he did not believe Sgt Bales and went back to sleep.
Afghan witnesses questioned via a video link described the horror of that night. A young girl in a bright headscarf recalled hiding behind her father as he was shot dead.
An army criminal investigations agent said Sgt Bales tested positive for steroids three days after the killings and other soldiers said he had been drinking on the evening of the massacre.
Prosecutors have pointed to statements Sgt Bales made after he was apprehended, saying they demonstrated a "clear memory of what he had done, and consciousness of wrongdoing".
The US military has not executed anyone since 1961.
There are five men currently facing military death sentences, but none for killings committed in war zones.