Kootenai County Sheriff Rocky Watson told reporters that human remains were found while searching a site in western Montana, and the remains have been sent to an FBI lab for DNA testing. There was no word on whether investigators believe the remains might be those of 9-year-old Dylan Groene.
Sheriff's Capt. Ben Wolfinger said Sunday that deputies believe Dylan is dead, based on information from Shasta and evidence from the stolen vehicle the suspect was driving.
He said interviews with the girl were going slowly at Kootenai Medical Center, where she has been since she was recovered early Saturday while eating at a Denny's restaurant with Joseph Edward Duncan III, a registered sex offender.
"She's a little girl and God only knows what she's been through in the last six weeks," Wolfinger said on CBS News' The Early Show. "We keep one investigator who is available for her to talk to… and we get little bits of information as time goes along."
Duncan, 42, of Fargo, N.D., was arrested and charged with kidnapping, but he has requested a lawyer and is refusing to talk to authorities, Wolfinger said.
CBS News Correspondent Cynthia Bowers reports that Duncan's home is also now being searched for clues.
Authorities said Duncan, who operated a chilling Web site in which he recently warned of upcoming violent deeds, will not be appointed a public defender until a court hearing Tuesday.
The two children were missing when authorities arrived at their rural home on May 16 and found the bound and bludgeoned bodies of their mother, Brenda; 13-year-old brother Slade; and their mother's boyfriend, Mark McKenzie.
Sunday night, the children's father, Steven Groene, spoke publicly for the first time about being reunited with his daughter.
"When I walked in the door, her face just lit up," Groene told Fox News, choking back tears. "She put her arms out and said 'Daddy, Daddy!' It was one of the better moments of my life."
"She looks real good," he said. "Very upbeat. She acts just like the little girl I saw three weeks before she disappeared."
Groene said police had instructed him not to ask Shasta questions about what had happened. He said he had never heard of Duncan before Saturday and still did not know much about the man. Authorities weren't telling him much about the evidence involving Dylan, either, he said, but they didn't tell him to give up hope.
"Obviously, in the case of Shasta, someone can be missing a long time and still come back safe," he said.
There was no sign of the boy when Shasta was found around 2 a.m. Saturday in the restaurant with Duncan.
Shasta was recognized by a waitress at the restaurant, who called police, and the little girl was reunited that afternoon with her father, Steve Groene.
The waitress explained on The Early Show how she stalled to keep Shasta and Duncan in the restaurant until police could arrive.
"Every child likes desserts," Amber Deahn said. "I proceeded to go through all of our dessert options. When she finally decided on a shake, I went through every possible combination of shake that we could make. And she decided on vanilla. It just took a little longer than normal to make it."
Duncan had spent more a decade in prison for sexually assaulting a 14-year-old boy at gunpoint, and at the time of his arrest was a fugitive from justice for allegedly molesting a boy in Minnesota.