The first day of Staff Sgt. Calvin Gibbs' court-martial at Joint Base Lewis-McChord in Washington began with opening statements and testimony by a witness who said Gibbs participated in the three deaths in 2010 then dismissed concerns they may have been witnessed, The Seattle Times reported Monday.
Gibbs' attorney said his client wasn't involved in two of the slayings and the third was a legitimate action against an armed enemy fighter.
"You will hear that Sgt. Gibbs was shot at. He returned fire in self-defense," attorney Phil Stackhouse said.
Gibbs also is accused of removing fingers from Afghan corpses and participating in an assault against another soldier. He pleaded not guilty to all charges.
Pvt. Jeremy Morlock, who pleaded guilty to three counts of premeditated murder for his role in the deaths, said Gibbs told him, "[As] long as we got our stories straight, no one was going to believe a bunch of locals."
As part of his plea agreement, Morlock agreed to testify for the prosecution.
In his cross-examination of Morlock, Stackhouse tried to discredit the witness by quizzing him on his use of hashish and other misconduct, some of which started when Gibbs joined the platoon in the fall of 2009, the Times said.
The court-martial shines light on U.S. war crimes in southern Afghanistan carried out by members of a platoon with Lewis-McChord's then-5th Brigade, 2nd Infantry Division.
Two other soldiers pleaded guilty to murder and one other pleaded guilty to involuntary manslaughter in the Afghan village killings.
If Gibbs is found guilty of any of three premeditated murder charges, an Army panel could sentence him to either life in prison or life in prison without parole, the Times said.
The trial is expected to last a week.