A military jury found the head of a rogue US army unit which killed Afghan civilians for sport guilty on all charges, at the end of a week-long court martial.
Staff Sergeant Calvin Gibbs was convicted on 15 counts, including three counts of premeditated murder for his role in the thrill killings while he was stationed in Afghanistan's Kandahar province.
After the five-person military panel gave its verdicts, the trial was set to move to the sentencing phase. The pre-meditated murder charges normally carry a life sentence.
Gibbs, 26, is the alleged ringleader of a so-called "kill team" responsible for a series of murders of Afghan civilians in southern Afghanistan between January and May last year.
Three members of the rogue army unit have already pleaded guilty in a scandal that has threatened embarrassment for the US military on the scale of the Abu Ghraib prison abuse in Iraq disclosed in 2004.
In closing arguments Wednesday, prosecutor Major Robert Stelle dismissed Gibbs's claims that he was responding to legitimate attack when the team killed the Afghans, before removing body parts and taking photos with the corpses.
"This is a case about betrayal, the ultimate betrayal. (Gibbs) betrayed his folk, he betrayed his unit, and with the flag of his nation emblazoned across his chest, thousand of miles from home, he betrayed his nation," Stelle said.
He was accused of setting up the killings, planting weapons on the dead civilians' bodies to make it look like they were fighters, and then removing fingers and teeth to show off to colleagues.
Gibbs's court-martial started last week, and in an unexpected appearance Friday he claimed his unit was engaged in genuine combat -- while admitting that he took fingers and teeth from the corpses.
"In my mind, it was like keeping the antlers off a deer you'd shoot... You have to come to terms with the things you're doing," he said.
But the military prosecutor dismissed those claims during a closing argument lasting over an hour at the Joint Base Lewis-McChord, south of Seattle, home to the 5th Stryker Brigade.
"Selling the engagement as legitimate was part of the plan," said Stelle, calling Gibbs's stories "fundamentally implausible."
Gibbs's lawyer countered by attacking the credibility of Private Jeremy Morlock and two other members of the "kill team," who received lighter sentences by pleading guilty and agreeing to testify against Gibbs.
In addition to attacking Morlock's statements, defense attorney Phil Stackhouse spent over two hours pointing out discrepancies in the evidence in an attempt to plant reasonable doubt in the minds of the five-soldier panel.
One of the major points of discord revolved around the barrel length of an automatic weapon allegedly "dropped" on a victim to make the killing appear justified.
The prosecution alleges that the AK-47-type gun was stuffed into Gibbs's backpack, but the defense said it was too big to fit in the closed pack, casting doubt on whether he could have used his pack to conceal the weapon.
Morlock said during the trial that Gibbs "had a general disdain for Afghans, and called them savages."
Stelle called the idea that Morlock and the other kill team members were willing to plead guilty to murder in an effort to foist blame onto Gibbs as "patently ridiculous."