The US soldier who massacred 16 Afghan villagers has apologised for his "act of cowardice" as he made his case for why he should one day have a shot at freedom.
Staff Sergeant Robert Bales said that he was operating "behind a mask of fear ... and bravado" when he went on a solo night-time mission and slaughtered villagers in mud-walled huts.
Bales, 39, pleaded guilty in June in a deal to avoid the death penalty for the March 11 2012 attacks. A jury is determining if his life sentence should offer a chance of parole.
Bales said that he was mad at himself for being angry all the time, drinking too much and hiding his problems.
In June, Bales could not explain to a judge why he committed the killings. "There's not a good reason in this world for why I did the horrible things I did," he said.
If he is sentenced to life with the possibility of parole, Bales would be eligible in 20 years, but there is no guarantee he would receive it. He will receive life with parole unless at least five of the six jurors say otherwise.
Defence attorneys are hoping to convince jurors that Bales simply "snapped" after four combat deployments and deserves leniency. They say he suffered from post-traumatic stress disorder.
Jurors this week have heard from Afghan survivors and family members of the victims who were flown to the US to testify.
Bales' attorneys did not question any of the Afghan witnesses.