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MIAMI (CBSMiami) – An investigation is underway after an overnight fire at a strip mall on Key Biscayne.

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Five businesses in the mall on Crandon Boulevard were damaged, either by the smoke and flames or the water used to put them out.

“I’m lucky no one was hurt, I’m very grateful to the fire department because they are amazing. We probably have one of the best fire departments in the country,” said Dr. Carmen Ortiz Butcher.

Butcher’s clinic has been in the mall for the last 12 years.

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“It started inside the wall and the firemen, who are wonderful, are very quick responders, they were here within minutes,” said Butcher. “They had to break into my office and through the side of my office to access the fire which was inside the wall in the roof. Because of that, they used their hoses and through that, I sustained some damage.”

More than 30 firefighters battled the flames and tried to keep it from spreading to other buildings including a nearby post office.

One firefighter was taken to the hospital where he was treated and released for minor injuries.

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The cause of the fire was determined to be an electrical problem.