Peter Millet / AP file
In this courtroom sketch, Staff Sgt. Robert Bales, left, appears before Judge Col. Jeffery Nance in a courtroom at Joint Base Lewis-McChord, Wash. on Aug. 20, during a sentencing hearing.
A U.S. soldier who shot 16 unarmed Afghan civilians in a nighttime raid apologized on Thursday at a sentencing hearing, calling the killings "an act of cowardice."
"Sorry just isn't good enough, but I am sorry," Army Staff Sgt. Robert Bales told a jury in a military courtroom in Washington state. "What I did is an act of cowardice."
Bales, who has been on four combat tours in Iraq and Afghanistan, has admitted to shooting the villagers, mostly women and children, in Kandahar province in March 2012.
He pleaded guilty in June to avoid the death penalty. The jury of six military personnel is tasked with deciding if he will spend the rest of his life in prison or if he will be eligible for parole after 20 years.
Defense lawyers have attempted to show Bales suffered a breakdown while on his final deployment to Afghanistan. They also said Bales suffered from post traumatic stress disorder and a brain injury before heading out on his last tour to Afghanistan.
Army prosecutors said Bales acted alone and with premeditation. Armed with a pistol, a rifle and a grenade launcher, he left his base twice during the night, returning in the middle of his rampage to tell a fellow soldier, "I just shot up some people."
On Thursday, Bales described his emotional and mental state leading up to the massacre.
He talked about coming back from his second deployment and feeling angry. He told the jury he would get mad sitting in traffic or washing dishes.
Bales said he also had headaches and was secretively drinking and taking sleeping pills. He said his state got worse after the third deployment. He told the jury he found a counselor on post but stopped going after a while because he didn't think it was helping him.
Before the fourth deployment, Bales said he was conflicted because he felt he needed to go for his soldiers, but he wanted to stay at home with his family. He described living in fear all the time: fear of the unknown, fear of doing something, fear of not doing something. His anger escalated, he said, and he often yelled at his troops.
Bales also apologized to the families of those he killed.
"If I could bring family members back, I would," he said.
"I'm sorry… I'm truly, truly sorry for those people I took away. I murdered their families."
The prosecution rested its case on Wednesday after calling to the stand a string of witnesses including nine Afghans, among them a man who lost six of his seven children in the attacks and a teenager who was shot in the legs but survived.
Reuters contributed to this report.