Three people were found dead at a house southeast of town in an "obvious" triple homicide, and an Amber Alert (search) for two children was issued Tuesday morning by the Kootenai County sheriff's office.

Authorities were called about 6:15 p.m. Monday by a neighbor who reported "suspicious circumstances" at the house about eight miles from town and just off Interstate 90 on Wolf Lodge Bay, an arm of Lake Coeur d'Alene (search), sheriff's Capt. Ben Wolfinger said.

The bodies bore obvious signs of injury, but the cause of death was not being released, Wolfinger said.

"They're treating it as an obvious homicide," Wolfinger said.

The Amber Alert covered all of Idaho, plus Spokane, Wash., and Malheur County, Ore. A message board on Interstate 90 just two miles from the family's home was flashing the alert Tuesday morning.

Authorities have no idea who took the children, Wolfinger said.

The victims in the house were identified as 40-year-old Brenda Groene, her 13-year-old son Slade, and 37-year-old Mark McKenzie, all of Coeur d'Alene.

An Amber Alert was issued for an 8-year-old girl, Shasta Groene (search), 3-foot-10 and 40 pounds with long auburn hair and hazel eyes, and her 9-year-old brother, Dylan Groene (search), 4 feet and 60 pounds, with a blond crewcut and blue eyes.

Both children lived at the house with their mother, sheriff's dispatch supervisor Barb McDonald said.

The children are pupils at Fernan Elementary School, and counselors at the school on Tuesday were prepared to talk to their classmates as needed, said Janet Feiler, spokeswoman for the Coeur d'Alene School District.

Wolfinger said the mother and father of the children are divorced. Investigators have talked with the father, and he is not considered a suspect or person of interest.

Tuesday morning, a dozen police cars and crime scene tape surrounded the small, cement-block house with a corrugated roof on a frontage road of Interstate 90. The frontage road was closed.

Sheriff's deputies, Idaho State Police and a team from the state forensics laboratory were examining the house and property. The investigation could take two days, Wolfinger said.

The Amber Alert system for children who may have been abducted and in imminent danger is named for 9-year-old Amber Hagerman of Arlington, Texas, who was killed after being kidnapped while riding her bicycle near her home in 1996.