An Amber Alert spanning into parts of three states was called after two children under the age of 10 were discovered missing from their home, where their mother, brother, and one other person have been found murdered.
Police used a helicopter and dogs to scour a forested area near the Coeur d'Alene, Idaho, home for any signs of Shasta Groene, 8, and her brother, Dylan, 9. Authorities said they had no clues as to their whereabouts. The FBI is also assisting in the search.
"Our main concern right now is the two children we cannot find," said Sheriff Rocky Watson.
Late Tuesday night, Sheriff's Captain Ben Wolfinger said that investigators are also looking for Robert Roy Lutner of Hayden, Idaho. Police say he is not a suspect, but because he is believed to have been at the family's home on Sunday, he is considered to be a "person of interest" and investigators would like to speak with him.
Lutner is reportedly driving a 1975 Silver Ford pickup with Idaho license plates K161057 or a 1990 white Toyota pickup with Idaho plates K308811.
The victims in the house are identified as Brenda Groene, 40, mother of the missing children; Slade Groene, 13, the children's brother; and Mark McKenzie, 37, of Coeur d'Alene.
Sheriff Watson said he did not know the relationship between McKenzie and the others, but news sources have reported he was the mother's boyfriend.
The Kootenai County Sheriff's office, which issued the Amber Alert, says it has no idea who took the children, reports CBS' Teri Okita.
"We don't have any leads of abduction, of direction of travel, or people of interests ... so we're just doing whatever we can," Watson said.
The bodies bore obvious signs of injury, but the cause of death remained unknown, he said. "They're treating it as an obvious homicide," Wolfinger said.
Wolfinger said the two missing children were not at school Monday, raising the possibility that they could have been abducted earlier.
The mother and father of the children are divorced and the children lived with their mother, Wolfinger said. Investigators have talked with the father, and he is not considered a suspect or person of interest.
Authorities were called about 6:15 p.m. Monday by a neighbor who reported "suspicious circumstances" at the house on a bay of Lake Coeur d'Alene, sheriff's Capt. Ben Wolfinger said.
Investigators have talked with the father, and he is not considered a suspect or person of interest, Okita reports.
"We've met the biological father of the children," Wolfinger said. "He doesn't know where the children are at; last he knew they were on the school bus heading home."
Police say the home was not the site of a murder-suicide, but rather a triple-homicide. They are hoping the public will see the children somewhere and call 911.