More than 500 Oregon Army National Guard soldiers are mobilizing this week for Iraq amid continued concerns over soldier suicides.

PORTLAND — More than 500 Oregon Army National Guard soldiers are mobilizing this week for Iraq amid continued concerns over soldier suicides.

Suicide has become an issue of troop readiness and force strength. Three Oregon Guard soldiers have died in combat since 2007 and 14 have died by suicide.

"We are often more dangerous to ourselves than the enemy," Gen. Peter Chiarelli, Army vice chief of staff, said about suicide nationally in a July report. Last month, a federal task force recommended suicide investigations also needed to focus on the last hours of a soldier's life.

The death of Sgt. 1st Class Matthew Gross, of eastern Oregon, on Feb. 25 was instrumental in each departing Guard soldier meeting face-to-face with a chaplain.

Gross was found dead in his locked car off a farm road outside Hermiston. The Umatilla County medical examiner ruled the death a suicide but Gross' family called for a second investigation and the case has been reopened.

Gross was making detailed plans for a second Iraq deployment when he abruptly left work at the Hermiston Armory on the day he died. Witnesses told investigators that Gross was having marital problems and had a March 1 appointment to make a new will.

His wife, who declined to talk to The Oregonian, told authorities they had separated but had tried to reconcile.

Five hours after he left work, Gross was found dead in his locked car just off a farm road, a gun on the seat next to him. A Umatilla County sheriff's deputy investigated and closed the case.

The Umatilla medical examiner never saw the body but concluded the death was a suicide based on the investigation and photographs. The death certificate he signed states that Gross died at home, and the medical examiner later acknowledged that the location cited was an error.

Gross' mother, Lynne, and brother, Tony, protested the conclusion of suicide.

Seventeen days after Gross was buried, the Umatilla County Sheriff's Office reopened his case. As a result, the Army's standard suicide investigation also remains open, hinging in part on the county's findings.

The Army historically has had fewer suicides per capita than civilians but that changed a year after the invasion of Iraq. By 2008, the Army rate surpassed the national average.

Since June 2007, of the 98 casualties with family ties to Oregon, 28 took their own lives, said Chief Warrant Officer Scott O'Donnell, who tracks Army, active-duty and reserve deaths. Thirty-six service members were killed in action. The others died from accidents or illness.

Veterans are not at greater risk of dying of natural causes or other violent death than any other civilian, according to research by Mark Kaplan, a suicide expert and professor at the Portland State University School of Community Health. Veterans of any age are more than twice as likely to commit suicide, Kaplan and his colleagues found.

On Thursday, the state Department of Human Services reported that Oregon's suicide rate is 35 percent higher than the national average.

"We now share the dubious claim, with Alaska, that we have more deaths from suicide than from car crashes every year," said Lisa Millet, the Oregon public health investigator on the study.