The fire was reported shortly after 3 a.m. and might have started on the porch of the two-story family house, said David Hosick, a spokesman for the Indiana Department of Homeland Security, which includes the State Fire Marshal.

By the time firefighters arrived, the house was fully engulfed, he said. Joseph Buchheit, 33, who had been visiting the house, was able to escape without any injuries. Mr. Buchheit, who was Paige Ridener’s boyfriend, attempted to re-enter the home but was unable to because of the heavy fire and smoke, officials said.

The cause of the fire remained under investigation, but the authorities said that there was no indication that it was intentionally set or that foul play was involved.

Josh South, who said he was a close friend of the family and who started a GoFundMe fund-raiser to help the family with expenses, declined to comment about the family for privacy reasons.

“Once the family has decided, they will release any info related to the this horrific tragedy,” he said in a Facebook message on Sunday.