US army soldiers with the 101st Airborne Division Alpha Battery 1-320th leave on a patrol from Combat Outpost Nolen in the village of Jellawar in The Arghandab Valley on September 5, 2010. (Picture used for illustrative purpose only) Image Credit: AFP

Seattle: New documents released by the US Army say a staff sergeant charged in a conspiracy to murder civilians kept Afghan body parts and threatened subordinates.

Staff Sgt. Calvin Gibbs is the most senior of five Fort Lewis-based Stryker soldiers charged in the deaths of three Afghan civilians earlier this year. His lawyer says he denies being part of any conspiracy and that the deaths were all "appropriate engagements."

In charging papers released Wednesday, prosecutors say Gibbs and others in his platoon also beat up a soldier who reported drug use in the unit, said they'd kill him if he kept talking about it and threatened him by showing him fingers that had been cut from an Afghan corpse.

Hearings in the case are expected to begin this fall.