The US soldier who ran amok last year killing 16 Afghan villagers has apologised for the massacre, calling it an "act of cowardice".
Staff Sgt Robert Bales was making a case for why he should some day be released, during his sentencing hearing at a Washington state military base.
The 39-year-old said he had been a "mass of fear... and bravado" at the time of the attack on 11 March 2012.
The father-of-two pleaded guilty in June to avoid the death penalty.
If he is sentenced to life with the possibility of parole, Sgt Bales could be eligible for release in 20 years.
'Drinking too much'
"I'm truly, truly sorry to those people whose families got taken away," he told Thursday's hearing at Joint Base Lewis-McChord.
"If I could bring their family members back, I would in a heartbeat.
"Sorry just isn't good enough, but I am sorry."
Prosecutors have disputed whether he actually does feel remorse, playing a recording of a phone call in which an incarcerated Sgt Bales and his wife laugh as they discuss the case.
His lawyers argued the conversation had been taken out of context.
The soldier said on Thursday he was mad at himself for being angry all the time, drinking too much and hiding his problems.
He was also taking drugs and alcohol at the time of the attack, while serving his fourth combat deployment.
Former professional football player Marc Edwards appeared in court as a character witness for him.
The ex-New England Patriots fullback said Sgt Bales had been an "unbelievable leader" in their time at high school in the US state of Ohio.
His older brother, William Bales, 55, also paid tribute to him.
"There's no better father that I've seen," he said of Sgt Bales. "If you brought the kids in here today, they'd run right to him."
Major Brent Clemmer, who served with Sgt Bales in Iraq, told the jury he could not believe him capable of such an atrocity.
Earlier this week, the jury heard in grim detail, compound by compound, how Sgt Bales attacked two villages in the middle of the night in Kandahar province, spraying bullets into mostly women and children.
Nine Afghans, who were flown out by the US Army to attend the court martial, have testified about how the attack changed their lives.
Among them was Haji Mohammad Wazir, who lost 11 family members, including his mother, wife and six children. He told the court the killings had "devastated" him.
Mr Wazir received $550,000 (£350,000) in compensation from the US government.
A total of nearly $1m in condolence money was paid to families over the incident.