Dan Bewley, News On 6

TULSA, Oklahoma -- Investigators are still trying to figure out what caused a deadly fire in an abandoned Tulsa warehouse Tuesday evening.

The fire broke out just after 8 p.m. Tuesday near Admiral and Trenton.

Witnesses said the fire happened very fast.

"It was pretty scary," Robert Doss said.

The building is abandoned now but it was once the home of the Gutierrez Brothers Banana House.  Firefighters spent much of Wednesday putting out hotspots and looking for places where the fire was still burning.

Witness described a fire that quickly took off.

"It was pretty intense," Debbie Doss said.

Debbie Doss lives next door to the warehouse. She was forced out of her home during the night and says flames were everywhere, making it very difficult for firefighters.

"Every time they got the fire out a little bit it would flare up more," she said. "It was not a nice thing to see and then to hear somebody was in there, that was even worse."

Investigators say the woman who died was found inside the building and she didn't have any identification on her so it could be quite some time before they know who she is.

Investigators believe the woman was only in her late 20's or early 30's.

"I see some flames, real, real quick like a gas explosion," William Brenes, another witness, said.

William Brenes was sitting in his big rig across the street from the warehouse. He says he looked up to see flames coming out of a small window on an overhead door.

"Real, real quick, real quick,," Brenes said. "I see some smoke in the backside of the building and then flames inside through the window."

Brenes was surprised to hear that someone was in the building. He says there was hardly anybody around when the fire started.

"I don't remember seeing people there, not at all," he said. "Few kids on the bicycle's here on the street, but nobody in there. I don't remember seeing anybody in there."

Investigators said they haven't found anything that was the obvious cause of the fire. News On 6 reporter Dan Bewley even asked specifically if they've found materials used to make meth inside the building and they said that they have not.