WEST SPRINGFIELD, Mass. (AP) – A New Hampshire Air National Guardsman has been buried, as family and colleagues continue asking why he killed himself the day after returning from the war in Iraq.

Sergeant David Guindon of Merrimack was buried Thursday in West Springfield, Mass., where he grew up. He was 48.

Guindon shot himself in the head last Wednesday, after a six-month tour in Iraq. He left no note. At the funeral, the Rev. George Farland said everyone quietly is asking, “Why?”

Air Guard Major Christopher Hurley said the four other airmen who served with Guindon are undergoing grief counseling and psychiatric evaluations to ensure they are readjusting to home life.

He said the guard is investigating Guindon’s death and one result may be changing procedures to help airmen readjust.

Guindon was one of five servicemen of the New Hampshire Air National Guard’s 157th Air Refueling Wing who returned from duty last Tuesday. The unit was stationed at Camp Anaconda near Balad, northeast of Baghdad.

“He felt a high degree of patriotism in wanting to serve,” said Major Christopher Hurley, commander of the Logistics Readiness Squadron of the NH Air National Guard’s 157th Refueling Wing.

Guindon’s unit was assigned to “a very, very deadly mission that airmen have never encountered before,” Hurley said.

“They integrated into the U.S. Army and they performed a security role, protecting coalition and Army convoys,” Hurley said. “They were trained as vehicle operators by the Air Force – so what they were called on to do over there was extraordinary.”

Hurley would not describe the mission’s details, but said the unit braved firefights and roadside bombs.

Guindon’s unit would have used M16 rifles and .50-caliber machine guns, said Capt. Greg Heilshorn, a public affairs officer for the NH Army National Guard.

Guindon will be receiving an award including remarks from his commander in Iraq saying he “displayed tremendous leadership and initiative under hostile situations,” Hurley said.

AP-ES-08-27-04 0952EDT