(TACOMA, Wash.) -- According to Army prosecutors, Staff Sergeant Robert Bales has admitted multiple times being behind a shooting rampage in Afghanistan this past March that killed 16 Afghan civilians.
They say Bales has stated that he was acting out of revenge for previous attacks and chillingly admitted he thought he was "doing the right thing."
Bales is accused of having gone on a shooting rampage on the night of March 11 in Afghanistan's Kandahar Province. He is alleged to have snuck out of his remote outpost in the middle of the night and gone on a shooting spree at two nearby villages, where he killed 16 and injured six.
Evidence is being presented at an Article 32 hearing for Bales at Joint Base Lewis-McChord outside of Tacoma, Wash. The military's equivalent of a civilian grand jury, at the hearing prosecutors will present evidence before a presiding officer who will determine if Bales' case should go to a court-martial.
Sporting a shaved head, Bales sat quietly in court with a stoic demeanor as he heard prosecutors recount new details of the shooting spree he is alleged to have committed.
In his opening arguments Army prosecutor Lt. Colonel Joseph Morse said Bales had returned to the camp with his weapons and entire uniform covered in blood, some of which was later matched to at least one of the shooting victims.
Morse said that when he returned to his base Bales' demeanor seemed "completely normal" and when told to disarm at gunpoint, he responded, "Are you F-in' kidding me?!"
The prosecutor said Bales has made multiple admissions to the shootings "that clearly show, with chilling premeditation...Staff Sgt. Bales murdered these people." That included telling a fellow soldier, "Hey Mac, I just shot some people."
Bales allegedly stated that he "thought I was doing the right thing" and that he was apparently motivated by revenge for previous attacks to his unit.
Testifying Monday was Bales' colleague, Corporal Dave Godwin, who was granted immunity for his testimony. Godwin recounted how he and Bales had been drinking alcohol prior to the shooting rampage. American troops serving in Afghanistan are expressly forbidden from drinking alcohol while in the country.
Drinking Jack Daniels whiskey with soda, Godwin said they and another soldier "weren't drinking to get drunk." They had watched a portion of the movie Man on Fire, about a former CIA operative who goes on a revenge rampage.
Before the shooting rampage, Bales allegedly told his fellow soldiers that he had a "disgruntled family at home" and that he did not care "whether he gets killed or not."
When they went sleep at 11 p.m. Godwin said there was nothing odd about Bales' behavior. He recalled being awoken at 12:30 a.m. by loud banging on the door from fellow soldiers who said Bales had gone missing. After a quick search did not turn up Bales, a fellow soldier remembered Bales having said he was going to the village, but thought he was joking.
When Bales returned to the outpost Godwin was one of the soldiers who ordered him to put down his weapons that included an M-4 rifle, a grenade launcher and a 40-millimeter grenade belt.
He recalled Bales yelling, "Did you rat me out, did you rat me out?!"
Godwin said in addition to the T-shirt and camouflaged pants Bales was wearing, he had a blue sheet tied like a cape around his neck.
According to Godwin, "he said something like I thought 'I was doing the right thing' as we were taking his stuff away and he had his hands on his head." He added Bales seemed "very coherent" and looked like "he got caught with his hand in the cookie jar."
The Article 32 hearing is expected to last two weeks and some survivors of the attack will testify via a live satellite feed from Afghanistan.
Copyright 2012 ABC News Radio