(CNN) -- Authorities in Tennessee are asking for the public's help to find two children presumed missing after a fire destroyed their home.
The children -- identified as 9-year-old Chloie Leverette and 7-year-old Gage Daniel -- were last seen Sunday around 6:30 p.m., approximately three hours before their home burned down, according to the Tennessee Bureau of Investigation, or TBI.
They lived with their grandparents in Unionville, Tennessee.
"After an extensive five day search, multiple fire experts have processed the scene and are unable to locate evidence that Chloie and Gage were victims of the fire. The location of Chloie and Gage are unknown at this time," the TBI said.
Investigators recovered the bodies of the grandparents, according to Kristin Helm, a TBI spokeswoman, and feel fairly certain they would have found the children if they had been there. They have no theories as to the kids' whereabouts.
The TBI concluded its search of the home Friday, Helm said. She said the biological parents of the children have been contacted and are cooperating.
There was nothing to indicate Chloie and Gage were home at the time of the fire, the spokeswoman said. The cause of the blaze was not immediately clear.
When asked whether the TBI fears for the children's safety, Helm responded: "Yes, because we have two children who are outside their personal zone of safety. ... We consider them endangered."
Meanwhile, the marquee outside Community Elementary School in Unionville has morphed into a makeshift vigil. Flowers and gifts are piled around a sign that reads: "Pray for Chloie and Gage's family."
Tim Miller, the school's principal, told CNN affiliate WTVF that he feels he's on an "emotional roller coaster."
"We're like the family. At this point, we don't know, but we would like to see closure," he told WTVF.
Chloie is 4 feet, 8 inches tall, weighs 75 pounds, has brown hair and blue eyes. Gage is described as 4 feet, 50 pounds, with brown hair and eyes.
CNN's Susan Candiotti and Richard Davis contributed to this report.