POLKVILLE, N.C. -- A brother and sister were killed in a house fire at the 100-year-old Cleveland County home where they were raised.

The bodies of Jerry Cook and Evelyn Buff were found near the rear door of the house on Ken McEntire Road near Polkville, where they grew up with their 16 siblings. Firefighters said it appears they were sleeping when the fire started, but something awoke them and they tried to escape but were overcome by the smoke and heat.

A passerby spotted flames coming from the farm house around 2:30 a.m. Thursday and called 911. Firefighters said the flames were already through the roof when they arrived.

The State Bureau of Investigation was called to the scene to investigate, but agents said they haven’t found anything suspicious. Investigators haven’t pinpointed an exact cause, but they looked closely at some of the electrical wiring and a fan. They said they believe the fire was accidental.

As investigators sifted through the rubble, family members gathered throughout the day at the site. Ruth Davis, one of the victims’ sisters, said the siblings are all leaning on one another to get through this tough time.

“(We’re all in) disbelief, just disbelief,” she said. “They were always there when I needed them.”

The fire chief said the investigation is ongoing.

He also said the family who lived in the home was so well known that many of the volunteer firefighters who responded knew the victims.