JOINT BASE LEWIS-MCCHORD, Wash. — The US soldier who massacred 16 Afghan civilians last year in one of the worst atrocities of the Iraq and Afghanistan wars was sentenced Friday to life in prison with no chance of parole — the most severe sentence possible, but one that left surviving victims and relatives of the dead deeply unsatisfied.
‘‘We wanted this murderer to be executed,’’ said Hajji Mohammad Wazir, who lost 11 family members in the attack by Staff Sergeant Robert Bales. ‘‘We were brought all the way from Afghanistan to see if justice would be served. Not our way — justice was served the American way.’’
Bales, 40, pleaded guilty in June in a deal to avoid the death penalty for the March 11, 2012, raids near his remote outpost in Kandahar province, when he stalked through mud-walled compounds and shot 22 people — 17 of them women and children. Some screamed for mercy, while others didn’t have a chance to get out of bed.
The soldier showed no emotion as the sentence was announced at Joint Base Lewis-McChord, south of Seattle.
His mother, sitting in the front row of the court, bowed her head, rocked in her seat, and wept.
An interpreter flashed a thumbs-up sign to a row of Afghan villagers who were either wounded or lost family members in the attacks.
‘‘I saw his mother trying to cry, but at least she can go visit him,’’ said Hajji Mohammad Naim, who was shot in the neck. ‘‘What about us? Our family members are actually 6 feet under.’’
The villagers, who traveled nearly 7,000 miles to testify against Bales, spoke with reporters and asked through an interpreter what it would be like for someone to break into American homes and slaughter their families.
Bales never offered an explanation for why he armed himself with a 9mm pistol and an M-4 rifle and left his post on the killing mission, but he apologized on the witness stand Thursday and described the slaughter as an ‘‘act of cowardice.’’
The six-member jury weighing whether he would be eligible for parole after 20 years took about 90 minutes to decide the case in favor of prosecutors who described Bales as a ‘‘man of no moral compass.’’
‘‘In just a few short hours, Sergeant Bales wiped out generations,’’ Lieutenant Colonel Jay Morse told the jury in his closing argument. ‘‘Sergeant Bales dares to ask you for mercy when he has shown none.’’
A commanding general overseeing the court-martial has the option of reducing the sentence to life with the possibility of parole.
Defense attorney Emma Scanlan argued for the lighter sentence, begging jurors to consider her client’s prior life and years of good military service and suggested he snapped under the weight of his fourth combat deployment. She read from a letter Bales sent to his two 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.’’
‘‘These aren’t the words of a cold-blooded murderer,’’ Scanlan said.
She also read from a letter sent by a fellow soldier, a captain who said that Bales seemed to have trouble handling a decade of war and death: ‘‘The darkness that had been tugging at him for the last 10 years swallowed him whole.’’
Prosecutors laying out the case for a life term argued that Bales’s own ‘‘stomach-churning’’ words demonstrated that he knew exactly what he was doing.
‘‘My count is 20,’’ Bales told another soldier when he returned to the base.
Morse displayed a photograph of a girl’s bloodied corpse and described how Bales executed her where she should have felt safest — beside her father, who was also slain.
Morse also played video of Bales returning to the base after the killings, marching with ‘‘the methodical, confident gait of a man who’s accomplished his mission.’’
Bales, an Ohio native who lived in Lake Tapps, Wash., was under personal, financial, and professional stress at the time. He had stopped paying the mortgage on one of his houses, was concerned about his wife’s spending, and hadn’t received a promotion he wanted.
‘‘Sergeant Bales commits these barbaric acts because he takes stock of his life,’’ Morse said. ‘‘Sergeant Bales thinks the rest of the world is not giving him what he deserves.’’
The closing arguments came a day after Bales apologized for the attack, saying he’d bring back the victims ‘‘in a heartbeat’’ if he could.