The witnesses were flown to Joint Base Lewis-McChord in Washington state by the U.S. military to testify Tuesday at the sentencing hearing for Bales, who pleaded guilty to killing the civilians -- most of them women and children -- as he moved through their village in Kandahar province, The New York Times reported.
"That bastard stood right in front of me," Haji Mohammed Naim, 60, testified. "I wanted to ask him: 'What did I do? What have I done to you?'"
A six-person military jury will decide whether Bales, 39, will spend the rest of his life behind bars or be eligible for parole one day. His guilty plea in June means Bales won't face the death penalty.
Prosecutors have portrayed Bales as someone who felt "inadequate as a soldier and a man" who was deep in debt, missing home payments, unhappy with his family and frustrated with a stagnant military career, the Times said. Weeks before the spree, Bales had been taking steroids and on that night of the killing, he drank whiskey with other soldiers and snorted Valium before slipping out of his combat post.
Defense lawyers countered Bales suffered from post-traumatic stress and a brain injury, and was under the strain of four deployments in 10 years, three to Iraq, and the last to Afghanistan.
When Bales pleaded guilty in June, he took responsibility for his crimes but has said he has no memory of what he did or why he did it.