TACOMA, Wash. — A decorated U.S. soldier, who gunned down 16 unarmed Afghan civilians in a nighttime rampage, apologized on Thursday, Aug. 22, at a sentencing hearing to determine his fate, calling the killings “an act of cowardice.”

Army Staff Sergeant Robert Bales, a veteran of four combat tours in Iraq and Afghanistan, has admitted to shooting the villagers, mostly women and children, in attacks on their compounds in Kandahar province in March 2012.

“Sorry just isn’t good enough, but I am sorry,” Bales told a jury in a military courtroom in Washington state. “What I did is an act of cowardice.”

“Sorry just isn’t good enough, but I am sorry,” Bales told a jury in a military courtroom in Washington state. “What I did is an act of cowardice.”

Bales pleaded guilty to the killings in June in a deal that will spare him 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 been seeking to show that Bales suffered a breakdown under the pressure of his final deployment to Afghanistan, and say he suffered from post traumatic stress disorder and a brain injury even before his last deployment.

Army prosecutors have said Bales acted alone and with chilling premeditation when, 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.”