Corpus Christi, TX- The investigation into an explosion at a Corpus Christi Beach extended stay motel remains open, but investigators said they have determined a natural gas buildup in a unit caused it, officials said.

The Sept. 16 explosion at Aquarium Inn & Suites injured three, including the manager Kim Royal, who is recovering in the burn unit at Brooke Army Medical Center in San Antonio. Corpus Christi Fire Marshal Andy Cardiel said the investigation will conclude once she is well enough to give an official statement.

“We’re confident it was a gas explosion,” Cardiel said, “but of course we want to know whether she smelled anything and any other information she can provide.”

Another delay was that the explosion destroyed so much of the evidence officials normally rely on.

Cardiel would not say which unit he believes the leak began in.

“Natural gas is a very safe product, however, given the proper circumstances it can accumulate and create an explosion.”