Kootenai County Sheriff Rocky Watson said Monday that "possible" human remains had been found at a site in western Montana, and would be sent to the FBI crime lab in Virginia for DNA analysis. That is expected to take three days.
Watson declined to answer questions, but the fact that he called a press conference at the place where reporters were following the Groene story indicated officials believe the remains were related.
"Unfortunately we believe Dylan to be deceased," Sheriff's Capt. Ben Wolfinger said after Watson's announcement. But until the remains are identified, they could not be certain, he said.
"We believe them to be human remains. That's why we're sending them to the FBI lab in Quantico to have that final, definitive test done to make sure that they are human and they are, in fact, Dylan's," Wolfinger told CBS News Early Show co-anchor René Syler.
Dylan and Shasta, 8, had been missing since May 16, when the bound and bludgeoned bodies of their mother, older brother and mother's boyfriend were found at their rural home near here. Shasta was spotted by employees and customers early Saturday morning eating breakfast with a man at a Denny's restaurant in Coeur d'Alene.
Officers arrested the man, Joseph Edward Duncan III, 42, on suspicion of kidnapping and other charges. Duncan, from Fargo, N.D., is a violent sexual predator who has spent much of his adult life in prison.
Authorities planned to formally charge Duncan with kidnapping and being a fugitive from justice, and have said more charges were possible. A judge ruled Monday that there was probable cause to keep Duncan in jail until an initial court appearance Tuesday.
The sheriff's office released a photograph showing a smiling Shasta hugging her father Steve at Kootenai Medical Center. Another photo showed her holding a doll. The photos do not show any apparent injuries from her nearly six weeks of captivity.
"She's a much happier little girl right now," Wolfinger said, adding she was listed in good condition.
Officers have interviewed the girl a couple of times, but details of what happened to the children are agonizingly slow in coming.
"She's certainly helped give us some direction and focus in the investigation," Wolfinger told Syler. "She's a strong little girl, but she's still an 8-year-old little girl. God only knows what he's been through the last six or seven weeks. The investigators that are processing this part of the case are taking it one step at a time. When she's able to talk to them, when she's willing to talk to them, giving them what information she can give them at those times."
Duncan has refused to cooperate, officials said.
At this point, investigators aren't saying whether there's any evidence linking Duncan to the murders of those found beaten to death at the Groene's rural home. It is believed that Shasta and Dylan witnessed the killings, reports CBS News correspondent Cynthia Bowers. Duncan is considered violent. He once raped a 14-year-old boy at gunpoint. He wrote "my intent is to harm society as much as I can, then die."
Other major questions include: Have the children been with him the whole time? And, if so, where have they been hiding?
"We've got a lot of questions left unanswered," Wolfinger said, and some 60 investigators from the local area, the Idaho State Patrol and the FBI are working the case.
Authorities have relied on information from Shasta, evidence from Duncan's stolen red Jeep Cherokee and some 100 new tips from the public in the search for the boy.
The tips have poured in since photos of Duncan and the Jeep were released, and many are "vehicle-specific and Duncan-specific," Wolfinger said.
Watson said the remains were found at "one of the possible locations in western Montana," but did not elaborate about the site.
"Investigators continue to follow all of the other leads in this complex case," Watson said. "This case continues to be the No. 1 priority for all agencies involved."
Shasta has provided helpful information, but Wolfinger declined to say exactly what the girl was telling officers. "It's a slow process with Shasta," he said. "We're taking that very slowly."
The children were declared missing when authorities arrived at their home May 16 and found the bodies of their mother, Brenda Groene, 40, brother Slade Groene, 13, and their mother's boyfriend, Mark McKenzie, 37.
Authorities believe Duncan and the children remained in the Northwest during the past seven weeks, but Wolfinger declined to say where. He also would not say if there was any evidence others were accompanying Duncan.
Steven Groene on Sunday night spoke publicly for the first time about being reunited with his daughter, and thanked the community for its support. He said his daughter was watching movies and had a vanilla shake and pancakes for breakfast.
"Shasta is doing very well and we all are very hopeful that Dylan will come home safely," he said.
Officials have not said why they believe the Groene family was targeted. Steve Groene said he had never heard of Duncan before Saturday. Authorities searched Duncan's Fargo apartment.
Duncan, who was raised in Tacoma, Wash., had spent more than a decade in prison for sexually assaulting a 14-year-old boy at gunpoint and was a fugitive at the time of his arrest for allegedly molesting a 6-year-old boy in Minnesota.
A registered high-risk sex offender, Duncan was released on $15,000 bail earlier this year after being charged with molesting the boy. Police in Fargo had been looking for Duncan since May, when he failed to check in with a probation agent.