Story highlights The victims are 4 and 3

Flammable material left next to a space heater caused the fire

(CNN) Two children, left alone in their Louisiana home, were killed in a house fire while their mother was out getting her hair styled at a salon, authorities said.

Fire officials say they are still piecing together what happened at the home in Bastrop on Monday evening. But "one thing is certain," said Brant Thompson, state fire marshal deputy chief. "Ciarria Johnson ... left her children unattended for hours as she was having her hair styled."

The victims are 4-year-old Ta'shae Thompson Johnson and her 3-year-old brother, Clifton Thompson Johnson.

Johnson told authorities that she arranged for a neighbor to look after her children. But she hadn't, the deputy chief said.

"Investigators later determined that Johnson, in fact, had made no such arrangements and that she had returned home only after being contacted about the fire," he said.

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