Police are working to identify human remains found among the charred debris of a burnt-out porta-potty in Florida.

Residents in a St. Augustine neighborhood reported they heard a loud boom about 6:30 a.m. Saturday around a house that was under construction.

"I heard there were flames 15 feet in the air," neighbor Jan Long told First Coast News. "Our land that borders that land is all burnt now."

First responders arrived about an hour later to find the porta-potty on fire. St. Johns County Sheriff’s Office spokesman Chuck Mulligan told The Associated Press that in his 32 years of law enforcement, he had never even heard of such a fire.

It was not clear how the porta-potty caught fire.

When the fire was extinguished, authorities said the remains of what appeared to be a female were found within the rubble. The remains have not been identified yet, and police have no received any missing persons reports.

"We are asking anyone who may have a family member or friend who has not been heard from and may be missing to contact St. John’s County Sheriff’s Office and ask for The Major Crimes Unit," the St. Johns County Sheriff's Office said in an email to reporters.

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