Another soldier, Pfc. Andrew Holmes, also faces charges in the case, but a start date for his court-martial has not been publicly announced.
In all, officials charged 12 U.S. soldiers in what they called a conspiracy to kill Afghan civilians and cover it up, along with charges they mutilated corpses and kept grisly souvenirs.
Morlock was the first of the five to face an Article 32 hearing, the military equivalent of a grand jury hearing, at Joint Base Lewis-McChord.
Holmes is charged with the premeditated deaths of three civilians, possessing a dismembered human finger, wrongfully possessing photographs of human casualties, and smoking hashish.
He is also accused of conspiring with Morlock to shoot at a civilian and then toss a grenade so it would appear that the soldiers were under attack.
All of the accused men were members of a 2nd Infantry Division brigade operating near Kandahar in southern Afghanistan in 2009 and 2010.
The three others facing murder charges are Staff Sgt. Calvin Gibbs, of Billings, Montana; Adam Winfield, of Cape Coral, Florida; and Spc. Michael Wagnon, of Las Vegas, Nevada.