By Jessica Mintz
TACOMA, Wash (Reuters) - A U.S. Army sergeant is due to go on trial on Friday charged with murdering unarmed civilians and taking body parts for war trophies as ringleader of a rogue platoon that terrorized villagers in Afghanistan's Kandahar province.
The court-martial of Staff Sergeant Calvin Gibbs, 26, marks the climax of an 18-month investigation of the most egregious case of atrocities U.S. military personnel are accused of committing during a decade of war in Afghanistan.
Pentagon officials have said the misconduct exposed by the case, which began as a probe into hashish use within Gibbs' unit, had damaged America's image around the globe.
Published photographs showing two fellow GIs posing with the bloodied corpse of an Afghan boy they had just killed have drawn comparisons to the inflammatory Abu Ghraib prisoner abuse scandal in Iraq in 2004.
Gibbs, from Billings, Montana, is charged with three counts of premeditated murder, as well as cutting fingers off dead bodies and beating a fellow soldier who had alerted superiors to widespread drug abuse within their unit.
Charging documents said he was found in possession of "finger bones, leg bones and a tooth taken from Afghan corpses."
If convicted of all charges, Gibbs faces a maximum sentence of life in prison without the possibility of parole.
Prosecutors have cast him as the chief instigator among five infantrymen from the 5th Stryker Brigade accused of slaying civilians in random killings staged to look like legitimate combat casualties.
Seven others soldiers were charged with various lesser offenses, ranging from assault for opening fire at civilians to using illegal drugs. Most have already reached plea deals.
About 30 witnesses are expected to testify during the court-martial, slated to run through next week at Joint Base Lewis-McChord near Tacoma, according to Army spokesman Major Christopher Ophardt.
The first day of proceedings will likely be devoted to selecting a jury panel and handling procedural motions.
The chief prosecution witness is expected to be the soldier described as Gibbs' right-hand man, Specialist Jeremy Morlock, sentenced in March to 24 years in prison after pleading guilty to three counts of murder for his role in the same killings for which Gibbs is accused.
They alone were charged with all three killings, which occurred in January, February and May of 2010 while the Stryker Brigade was deployed in western Kandahar province.
Morlock, who originally implicated Gibbs in statements to military investigators, testified against him in open court during an evidentiary hearing in July as part of the plea deal he reached with prosecutors.
It was Morlock who appeared in photographs published in March by two magazines showing him crouched smiling over the body of a 15-year-old Afghan, holding the boy's head up for the camera by his hair.
A similar photo was published of another member of the self-styled Stryker "kill team," Andrew Holmes, who pleaded guilty last month to a single count of murder and was sentenced to seven years in prison.
A third co-defendant, Adam Winfield, pleaded guilty to a reduced charge of involuntary manslaughter and was sentenced to three years in prison in August, and a fourth, Michael Wagnon, still faces a court-martial.
All but one of the seven men charged with lesser crimes have received convictions and sentences ranging from demotion or dishonorable discharge to 60 days hard labor and jail sentences of up to nine months.
(Writing by Steve Gorman; Editing by Jerry Norton)