PORTER, Ind. (AP) — A natural gas explosion is suspected in a house fire that injured seven people including a 3-year-old girl, authorities said Friday.

The girl was freed from debris and airlifted to a Chicago hospital, and the others who were injured were taken to other hospitals for treatment, the Indiana fire marshal’s office said.

Three of the seven people have been released from hospitals, Porter Fire Chief Jay Craig told The (Northwest Indiana) Times on Friday.

The case remains under investigation by state and local officials, a spokesman with the Indiana Department of Homeland Security.

The identities of those injured were not being released immediately, he said. The status of those remaining in hospitals was unclear.

The fire occurred around 4:30 p.m. Thursday at a single-family home, Craig said.

Firefighters were met with heavy flames in the back of the home and damage throughout the structure, Craig had said.

“We had several bystanders and law enforcement show up and through collective efforts of all of them they were able to find the 3-year-old and get her out and to the ambulance,” he said. “Also during that search, they found another female trapped in the building and were able to get her out and stabilized.”

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