(CNN) -- A sergeant accused of killing five comrades at a combat stress clinic at a U.S. base in Iraq more than three years ago is mentally fit to stand trial on charges of premeditated murder, the Army said.
The Army announced the charges Friday against Sgt. John M. Russell, who faces a possible death penalty if convicted of one of the worst cases of soldier-on-soldier violence to arise during the war in Iraq.
Russell, 47, of Sherman, Texas, was charged with five counts of premeditated murder, one count of aggravated assault and one count of attempted murder in the May 11, 2009, shooting spree at the Combat Stress Center at Camp Liberty, a sprawling U.S. military base at the time on the outskirts of Baghdad.
"The charges are merely accusations and Sgt. Russell is presumed innocent until proven guilty," the Army said in a statement announcing the filing of charges.
The charges come nearly three years to the day of the shooting spree that sparked a review of the Army's mental health program in Iraq, and raised questions about how well prepared it was to deal with the issue of combat stress in deployed troops.
Russell is accused of killing two officers, members of clinic staff, and three enlisted soldiers who were seeking treatment.
At the time of the shootings, Russell was three months from wrapping up his third deployment to Iraq, according to his service record. He was a communications specialist with the 54th Engineering Battalion out of Bamberg, Germany, that was under the command of a unit from Joint Base Lewis-McChord.
At the time, senior defense and military officials told CNN that Russell was at a counseling session when he "became hostile and an altercation broke out." Russell's commander had earlier taken his weapon out of a concern that he might hurt himself.
A review of the incident and mental health procedures in Iraq, ordered by commanders and made public in October 2009, said Russell was escorted from the clinic by the military police. A short time later, according to the review, he struggled with one of the police, grabbing his weapon and then returning to the clinic where he allegedly opened fire.
Killed in the shootings were: Army Maj. Matthew Houseal, Navy Cmdr. Charles Springle, Army Staff Sgt. Christian Bueno-Galdos, Spec. Jacob Barton and Pfc. Michael Yates Jr.
The charges filed this week by the Army follows a finding that Russell was mentally fit to stand trial. He was initially determined to be incompetent to stand trial.
Russell's attorney, James Culp, did not immediately respond to a CNN request early Saturday for comment.
A trial date for Russell has not been set, the Army said.