POLSON (AP) — Sgt. Lucas T. White, whose mother and stepfather live here, was killed in action in Iraq, his mother said Wednesday.

White lived in Pendleton, Ore., until he was 12 or 13, said his mother, Julie Brooks. The family then moved to White Swan, Wash., where White finished high school in 1998.

A member of the Montana National Guard visited Brooks and White’s stepfather, Lyle Brooks, on Monday to inform them of their son’s death.

White, 28, was leading a striker patrol in Baghdad when his unit was ambushed by small arms fire and an improvised explosive device, Brooks said.

The incident is under investigation by the U.S. Army.

White, a member of the Confederated Tribes of the Umatilla Indian Reservation in Oregon, enlisted in the Army in 2001 and served in Afghanistan. He re-enlisted and had been in Iraq for five months.

‘‘He really enjoyed what he was doing,’’ Brooks said. ‘‘We’re so proud of him.’’

She said a service was held in Iraq. White’s body will be returned to White Swan on Thursday for a traditional American Indian ceremony.

At White’s request, the family has arranged for his interment at Arlington National Cemetery in Virginia.

In addition to his mother and stepfather, White is survived by his father, Mervin White of Spokane; brothers Marcus Ramos, Nathaniel and Seth Brooks and sister Melissa, all of Polson; his grandparents and several aunts and uncles.