Amber Alert for 2 children after Tenn. fire

AP This combination of undated photos provided by the Tennessee Bureau of Investigation shows Gage Daniel, 7, left, and Chloie Leverette, 9. The two children are now considered missing and in danger, investigators said. By NBC News and wire services Authorities in Tennessee have issued a statewide Amber Alert for two young siblings who have missing since their grandparent's home was destroyed by a fire. "We don't know where they are," Tennessee Bureau of Investigation spokeswoman Kristin Helm told WSMV-TV. "We don't have any indication that they're in another state." Authorities issued the alert late Friday evening after investigators spent a fifth day trying to determine if there were any remains of the children in the fire debris. The children, identified as Chloie Leverette, 9, and Gage Daniel, 7, were living with their grandparents at the house that burned Sunday night and early Monday. Choking back tears at times, Gage's father, Christopher Daniel, said he had no idea what could have happened to the children. "I don't know what to think. I don't know what to think," Daniel told The Associated Press. "They don't think that they burned up in the fire, the way I took it they don't." The children have not been seen since before the fire Sunday night. Two bodies tentatively identified as 72-year-old Leon "Bubba" McClaran and his wife, 70-year-old Molli McClaran, were recovered Monday and have been sent to the Nashville medical examiner's office for autopsy. She was the children's maternal grandmother, he their step-grandfather. Watch the Top Videos on NBCNews.com "To err on the side of caution, as far as law enforcement is concerned, we feel like we can leave no stone unturned and just try to follow every lead that we can to ensure that they're not somewhere else," Helm told WSMV-TV in Nashville. "I don't know where else they would be. They were a close knit family." Multiple fire experts had processed the debris of the incinerated farmhouse and no trace of the children was found, authorities say. Helm said the TBI does not have any direct evidence that the children are victims of foul play. She said there are no persons of interest in the case and that investigators are following all leads, but would not elaborate. Forensic teams from Middle Tennessee State University and the University of Tennessee at Knoxville were brought in to help in the search. Forensic anthropologist Steven A. Symes, who formerly worked in the medical examiner's office for Shelby County, said it was a smart decision for authorities to bring in these teams because they have the expertise. "It just takes some screening and some close looking and understanding that a piece of drywall and piece of skull bone burned look about identical," he said. Symes said the recovery of remains from fires has advanced as the forensic anthropology field grows, but he acknowledged it is still a slow process. He said the length of time to recover remains depends on the scene and how detailed the search is. "Unfortunately sometimes a case that you least expect to be suspicious or difficult turns into that type of case," he said. Neighbor Erika Barnet said she was starting to come to terms that her neighbors may have died in the fire, but now says she doesn't know what to think. "It was just fire everywhere," Barnett told WSMV-TV. "As hot as that fire was over there, I don't see how they would have gotten out." The Associated Press contributed to this report. More content from NBCNews.com: 'Smiles': New street drug tied to 'Sons of Anarchy' death Wolf pack that killed cattle taken out by sharpshooters World War II bombs in Gulf of Mexico need to be checked, experts warn Video: Cheerleaders raise special-needs girls' spirits Lawsuit: Pentagon denied rape victims their constitutional rights US immigration chief: Same-sex ties are family ties A country song about PTSD: 'All you've got left are these pieces' Follow US News from NBCNews.com on Twitter and Facebook