Witnesses at a military hearing for a U.S. soldier accused of shooting and killing five fellow service members in 2009 at a mental health clinic in Iraq testified Monday that Army Sgt. John Russell was frustrated at the psychiatric care he was receiving.

The testimony came in the first day of a hearing at Fort Leavenworth on whether Russell will face a military trial. He is charged with five counts of premeditated murder, two counts of attempted premeditated murder and one count of assault.

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

Michael Jones testified via telephone that he also saw Russell the day before the shooting for the first time and prescribed an antidepressant to treat his symptoms.

Russell left Jones' office shortly after the counseling session began on May 11, 2009. Jones said Russell indicated he had enough with the treatment he had been receiving and stormed out of the clinic.

Jones differed with witness accounts that he yelled at Russell to return to the clinic.

"I was emphatic. I made sure he heard me that the best thing to do was to come back into the building," Jones said.

Russell is accused of carrying out the deadliest act of soldier-on-soldier violence in the war in Iraq. He was nearing the end of his third tour at the time. He was present at the hearing, sitting with his defense team. It is unclear if he will testify during the proceedings, which are scheduled to last several days.

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

Families of the victims wept as prosecutors showed witnesses photos taken from the combat stress clinic and described the incident.

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.

Russell was assigned to the 54th Engineer Battalion of Bamberg, Germany.

Staff Sgt. Enos Richards testified that he was ordered to escort Russell to the mental health clinic about 30 to 45 minutes away. Richards said Russell wasn't in his appointment long before it ended and military police were called to assist.

Richards said after the officers came and the situation calmed down he and Russell returned to their unit. Russell said little, if anything, on the return trip.

Richards said when he shut off the white Ford Explorer and got out, Russell reached behind and grabbed Richards' M-16 rifle, loaded it with a 30-round magazine and took the safety off.

He then demanded the keys to the vehicle.

"He said 'Give me the keys or I will shoot you," Richards said.

Russell then drove off and allegedly returned to the clinic.

Richards testified it took several minutes to convince fellow soldiers that Russell had stolen his weapon and his vehicle.

Richards said he and others searched the soldiers' housing area to see if Russell had returned there to take his own life. They then realized the other place he may have gone was the stress clinic.

Richards said someone at the headquarters called the clinic and heard the shots being fired.

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.

Special Agent Abass Golfrey was assigned to the Army Criminal Investigation Division at Camp Liberty located about "a stone's throw" from the combat stress clinic. Golfrey said an agent out on a smoke break heard the shots fired next door and agents responded.

Golfrey, who is also with FBI's office in New York, said while agents went through the front door, he went around the building and found Russell walking calmly across the yard, an odd sight compared to others he saw fleeing the mayhem.

"At the time, I didn't think he was the shooter," Golfrey said, later learning he mumbled to another agent that he may have killed somebody.

Golfrey said Russell had blood on his shoe laces and wasn't wearing his name tape on the front of his uniform, which was found inside the SUV. He was unarmed, having laid down the rifle as he walked away.