(CNN) -- The Army sergeant who admitted to gunning down 16 civilians in a 2012 rampage through two villages near his outpost in southern Afghanistan is expected to take the stand at his sentencing hearing and will apologize.
Army Staff Sgt. Robert Bales pleaded guilty in June to more than 30 criminal charges, including 16 premeditated murder counts.
The plea spares the 39-year-old Bales the prospect of a death sentence in the killings. He now faces life in prison, but a jury of four officers and two enlisted personnel will decide whether he will have a chance at parole.
"Yes, Bob will take (the) stand ... Yes, Bob will apologize," Bales' lawyer, John Henry Browne said in an e-mail to CNN.
Bales admitted to slipping away from his outpost in southern Afghanistan and going on a house-to-house killing spree in two nearby villages in March 2012, a massacre that further strained ties between American troops and their Afghan allies.
But he has not offered an explanation for his actions.
"I've asked that question a million times since then. There's not a good reason in the world for the horrible things I did," Bales said when he pleaded guilty, according to Drew Mikkelson of CNN affilliate KING, who was tweeting from the courtroom.
Mikkelson also tweeted from the sentencing hearing, which began this week at Joint Base Lewis-McChord, near Tacoma, Washington.
So far, a number of Afghan civilians have taken the stand for the prosecution to talk about what they saw and survived.
Haji Mohammed Wazir lost 11 relatives -- his wife, mother, two brothers, a 13-year-old nephew and six of his seven children -- according to KING.
"My life has never been the same," Wazir told the jury.
It's been more than a year since the massacre, but Wazir said: "I feel like it's happening right now," the affiliate reported.
KING's Mikkelson tweeted that a 12-year-old boy who survived the rampage testified about seeing his father and sister get shot.
Another witness broke down on the stand and cried out: "For God's sake, don't ask me any more questions," Mikkelson wrote.
In addition to the murder counts, Bales pleaded guilty to six counts of attempted murder, seven of assault and the use of illicit steroids and alcohol. He pleaded not guilty to a charge of obstruction of justice.
Bales is a member of the Army's 3rd Stryker Brigade Combat Team, an element of the 2nd Infantry Division. His attorneys have said the service made a mistake in assigning Bales to another combat tour despite evidence of post-traumatic stress disorder and a traumatic brain injury suffered during a combat tour in Iraq.
CNN's Matt Smith contributed to this report.