The victims likely died from smoke inhalation, since their burns were not substantial, said coroner John Walters.
All six people were tenants in the single-story house.
Authorities believe a malfunctioning electrical outlet sparked the fire, said Ken Meredith, an investigator with the state fire marshal's office. A smoke detector was found in the home, but the batteries were disconnected, investigators said.
All six people lived as renters in the single-story house, officials said.
Killed were Tracy Caraway Whitney, and her three children: Cristian, Adrian and Majellica. Gary Matheny, 39, also died in the fire.
Matheny's wife, Elizabeth Matheny, 45, was hospitalized in critical condition Monday.