(T-G photo by David Melson)
Their painstaking hand-sifting of ashes and debris for any remnants of the bodies of Chloie Leverette, 9, and Gage Daniel, 7, was to no avail, authorities said.
"They've found absolutely nothing," Sheriff Randall Boyce said.
Bedford County fire chief Mark Thomas also said nothing related to the children was discovered.
Still more searches of what's left of the singed home continued today, officials said.
"We're still going through and sifting the rest of the debris," Bedford County fire chief Mark Thomas said this morning.
Teeth mentioned earlier by Thomas as having been found in the debris and taken to a dentist for inspection did not belong to one of the children, Thomas said.
"They turned out to be some old dental work," the chief said.
The fire may have been fueled by gas tanks in the home, according to the fire chief.
"We found about 30 to 35 gas grill bottles in the basement," Thomas said. "From time to time they would explode when we were fighting the fire."
Blue flames, indicating the presence of gas, were occasionally visible Sunday night.
The agencies which have been conducting the search since Sunday's blaze which also took the lives of Leon McClaran, 72, and Molly McClaran, 70, were joined by additional help Thursday.
Agents from the Tennessee Bureau of Identification, the state's arson and bomb squad, the University of Tennessee forensics department and Shelbyville Police Department detectives worked alongside Bedford County firefighters and deputies, Boyce said.
TBI issued an Endangered Child Alert on Wednesday after Boyce listed the children as missing instead of dead because no traces of their bodies were found.
Boyce and the TBI said Wednesday that change does not indicate a belief that the children were alive, despite an initial state press release that indicated otherwise.
TBI officials said Thursday no information from interviews with family members and friends has led them to believe the children are alive.