The U.S. soldier accused of shooting and killing five fellow servicemembers at a clinic on Camp Liberty, Iraq, last month is being held at a Marine Corps detention facility in Virginia while undergoing "evaluations" at Walter Reed Army Medical Center, Army officials confirmed Thursday.

Sgt. John M. Russell, 44, of the 54th Engineer Battalion out of Bamberg, Germany, has been charged with five counts of murder and one count of aggravated assault in the May 11 shootings, which killed an Army officer and a Navy officer on the clinic staff along with three enlisted soldiers who were at the clinic.

Russell is being held at the Marine detention facility in Quantico, Va., during the evaluations, two Army officials confirmed.

"At the conclusion of the evaluations, he will be returned to the confinement facility in Kuwait," said Col. Jerry O’Hara, a spokesman with 3rd Army.

Officials would not say what the evaluations entail, nor did they have information on when or where an Article 32 — the military’s equivalent of a grand jury hearing — would take place.

The shootings are the worst case of soldier-on-soldier violence in the Iraq war and highlight the strains faced by troops who undergo repeated combat deployments.

Russell, who was on his third Iraq deployment, had been ordered to turn in his weapon and receive counseling at the Camp Liberty clinic. Shortly after a confrontation with clinic staff on May 11, he returned to the clinic with a gun, possibly wrestled from his escort, and began shooting, the military has alleged.

In interviews shortly after the incident, Russell’s family said he faced multiple stresses, including mortgage debt and conflict with a unit commander.

Russell joined the National Guard in 1988 and the active Army in 1994, officials have said.

Stars and Stripes reporters Jeff Schogol and Dan Blottenberger contributed to this story.