WASHINGTON - A US Army serviceman accused of murdering unarmed Afghan civilians for fun is to face trial in a military court that could result in life imprisonment without parole, according to media reports. Lt. Gen. Curtis Scaparrotti, the commander at Joint Base Lewis-McChord in the US state of Washington, announced the decision Friday for a high-profile Army prosecution of the accused Staff Sargeant Calvin Gibbs. Gibbs is reported to be the ringleader of a group of rogue soldiers who allegedly killed three unarmed Afghans and then tried to stage the deaths to make them appear like legitimate battlefield casualties. He faces charges that include murdering three unarmed Afghan civilians, keeping body parts as grisly war trophies and beating a whistle-blower who told superiors about widespread hashish use in his unit. Gibbs, 25, is one of five soldiers from the Stryker Brigade charged with murder. Twelve soldiers in all face charges in the most serious prosecutions of alleged war atrocities by US military deployed in Afghanistan since the war began in 2001. In the fall, the Army held a pretrial hearing that enabled prosecutors to lay out their case to an investigating officer. Col. Thomas Malloy recommended one of the three murder charges be dropped because it could be difficult to prove beyond a reasonable doubt. But Scaparrotti opted to press forward with all three murder charges for killing unarmed Afghans in January, February and May last year. During that time, Gibbs was a squad leader with a platoon of the 5th Brigade, 2nd Infantry Division.