SEATTLE • Last December, Army Staff Sgt. Calvin Gibbs began joking with other soldiers about how easy it would be to "toss a grenade" at Afghan civilians and kill them, ...

Army prosecutors allege two more Afghan civilians were subsequently killed, one during a patrol in February and another in May, in a brutal plot led by Staff Sgt. Calvin Gibbs and Cpl. Jeremy Morlock.

Staff Sgt. Calvin Gibbs of Billings, Mont., was the highest ranking of five soldiers charged in the deaths of the unarmed men during patrols in Kandahar province early last year.