Staff Sgt. Robert Bales, the US soldier who murdered 16 Afghan villagers last year, has been sentenced to life in prison without the possibility of parole.

Robert Bales, 39, opened fire on men, children and women during the attack in Kandahar province last March.

He pleaded guilty to the massacre in June to avoid the death penalty.

Robert Bales apologized for the massacre during his sentencing hearing at a Washington state military base on Thursday, calling it an “act of cowardice”.

He had been making a case for why he should one day be eligible for parole, which would have meant he could potentially have been released in 20 years.

But on Friday the military jury of six at Joint Base Lewis-McChord ruled against him.

Robert Bales showed no emotion as the sentence was announced. His mother bowed her head, rocked in her seat and wept.

Afterwards Afghan villagers who were flown out by the US Army to attend the trial spoke to reporters.

Staff Sgt. Robert Bales has been sentenced to life in prison without the possibility of parole

“We wanted this murderer to be executed,” one man said through an interpreter, according to local media.

“We came all the way to the US to get justice. We didn’t get that.”

Sgt. Robert Bales was serving his fourth combat deployment when he attacked two villages in the middle of the night, spraying bullets into mostly women and children.

His lawyers argued that post-traumatic stress disorder and a brain injury were factors in the killings.

Nine Afghan villagers testified at the court martial.

Among them was Haji Mohammad Wazir, who lost 11 family members, including his mother, wife and six children.

The jury returned the sentence just hours after the prosecution and defense made closing arguments.

Prosecutor Lt Colonel Jay Morse showed jurors photos of a young girl who was killed as she screamed and cried.

In his closing arguments, he showed surveillance video of Sgt. Robert Bales returning to his base with what he said was “the methodical, confident gait of a man who’s accomplished his mission”.

“In just a few short hours, Sgt Bales wiped out generations,” Jay Morse said.

“Sgt. Bales dares to ask you for mercy when he has shown none.”

Defense lawyer Emma Scanlan read a letter the soldier sent to his children 10 weeks before the killing: “The children here are a lot like you. They like to eat candy and play soccer. They all know me because I juggle rocks for them.”

She told the court: “These aren’t the words of a cold-blooded murderer.”

While Emma Scanlan said she would not try to minimize what Sgt. Robert Bales did, she asked jurors to consider his earlier military service and give him a “sliver of light” – the possibility of parole.

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