An 11-year-old Navajo girl kidnapped from a school bus stop has been found murdered in the hills of America's largest Indian reservation. Ashlynne Mike's parents contacted police after the girl and her nine-year-old brother, Ian, vanished as they waited to return home after a day of school in the town of Fruitvale, New Mexico, west of Albuquerque.

After the missing person's report, a motorist picked up Ian as he walked alone in the dark that night along a reservation highway. The boy told police that a Native American man had driven up to the bus stop and asked the siblings and another boy if they wanted to go to a movie.

Only Ashlynne was initially lured into his van, according to her brother. Ian was suspicious but accompanied her, he said, because he didn't want his sister to be alone with the driver.

The man drove with the children into desolate hills at the edge of the Navajo Nation reservation, let Ian out of the car, then walked away with Ashlynne. He later returned without the girl, and told Ian, who was still waiting at the spot, to "go home," said Najavo Nation spokesman Mihio Manus.

The frightened boy ran more than two miles to a highway where the motorist picked him up. Ian was "so tired and just crying and crying for his sister," his aunt, Darrell Foster-Joe, told CBS News. "It was really hard for the FBI to get any information from him." Foster-Joe described Ashlynne as a fun-loving, quiet and kind girl.

Federal, tribal, state and county officers on the ground, New Mexico State Police in a helicopter and some 80 residents searched for the girl. Her body was found near Shiprock Pinnacle, a distinct rock formation that the nearby town of Shiprock is named for.

"We were very hopeful that we would find her in good shape," said Navajo public safety officer Jess Delmar. "We found her but it didn't turn out well." Police did not release details of the crime.

Investigators are now poring over the area in a hunt for clues into Ashlynne's murderer. Authorities described the kidnapper as a light-skinned Native American in his 20s or 30s with a teardrop tattoo under his left eye who drove a maroon van with a luggage rack but no hubcaps.

Tips and sightings of the man and his van are coming in from across the reservation that spans parts of New Mexico, Arizona and Utah. FBI officials said agents are following up on all leads.

"We're leaving no stone unturned," FBI Special Agent in Charge Terry Wade told reporters during a brief news conference. "We will solve this case and give Ashlynne Mike's family the justice they deserve."