Fort Leavenworth ? A soldier stormed into a U.S. combat stress clinic near Baghdad shortly after leaving a counseling session, opening fire on fellow service members who cried out “oh God, oh God” as they were shot, witnesses said Tuesday during a hearing that will determine whether the alleged gunman stands trial.

Sgt. John Russell, 46, is facing charges including five counts of premeditated murder for the May 2009 attack at Camp Liberty, which was the deadliest act of soldier-on-soldier violence during the war in Iraq. The case cast a spotlight on combat stress, morale and mental health issues as troops increasingly served multiple combat tours.

Sgt. Dominic Morales testified Tuesday that he and two other soldiers took cover in an office as Russell walked through the clinic shooting. Morales said he heard soldiers who were hit yelling out, “oh God, oh God.”

The father of Army Sgt. Christian E. Bueno-Galdos, who was among those killed, was overcome during the testimony and left the courtroom at Fort Leavenworth. A military judge is hearing testimony at the Kansas post, where Russell is being held, during proceedings similar to a civilian grand jury.

The shootings killed Navy Cmdr. Charles Springle, 52, of Wilmington, N.C., and four Army service members: Bueno-Galdos, 25, of Paterson, N.J.; Pfc. Michael Edward Yates Jr., 19, of Federalsburg, Md.; Dr. Matthew Houseal, of Amarillo, Texas; and Spc. Jacob D. Barton, 20, of Lenox, Mo.

The killings triggered an investigation, resulting in a 325-page report that was critical of the way the military was handling mental health issues while soldiers were deployed. In the report, Russell’s unit acknowledged that it lacked the policies and procedures to effectively guide or treat soldiers who were suffering from combat stress or deemed at-risk of incident.

Russell, who grew up in a small Texas town north of Dallas, had been ordered to seek counseling after reporting he was suicidal. He was assigned to the 54th Engineer Battalion of Bamberg, Germany.

Former soldier Leilani Boyer, who served in the same unit with Russell on two deployments to Iraq, testified that she confronted Russell in the weeks before the shootings about comments he made about her being late to work and others that embarrassed her in front of her peers. She said she thought the unit was giving him special treatment because he “was a slow learner” of new technology.

But she also said that during a smoke break with Russell days before the shooting, his eyes were “glossy” and he seemed troubled. She knew he’s been to counseling at a combat stress clinic but was forced to leave, so she told him to try another one at Camp Liberty.

“He didn’t seem like Sgt. Russell. I felt sad for him, especially in a combat zone,” Boyer said.

On Monday, the first day of the hearing, former Army Reserve psychiatrist Michael Jones testified that Russell was clearly angry and irritated during a brief encounter they had on the day of the shootings, May 11, 2009. Russell had been ordered to seek counseling after reporting to his commander earlier in the day that he was suicidal.

Jones testified via telephone that he saw Russell the day before for the first time and prescribed him an antidepressant. Russell left Jones’ office shortly after the counseling session began May 11, 2009. Jones said Russell indicated he’d had enough with the treatment he’d been receiving and stormed out of the clinic.

During Tuesday’s testimony, Staff Sgt. Bryan Benz, a military police officer in Iraq at the time of the shooting, said it was policy that two officers escort any suicidal soldier to be evaluated and observed by mental health staff.

Benz said he thought that was what was happening when he responded to the stress clinic when Jones and Russell had their encounter. However, Benz said Jones wanted Russell removed from the clinic and to “come back when he could control his anger.”