UPDATE: No one trapped inside DeKalb business fire

DeKalb County authorities are investigating a massive fire that ripped through an abandoned doctor’s office and shut down a busy road for more than three hours Monday.

Officials thought someone who was trying to escape frigid temperatures might have been trapped inside the two-story building in the 4800 block of Redan Road, DeKalb fire Capt. Eric Jackson said.

They later learned that was not the case, he said.

The fire department got the initial call about the blaze just after 6:15 a.m.

When a crew arrived, they found heavy flames and a thick cloud of smoke. Redan Road was shut down.

Firefighters tried to access a hydrant but were instantly delayed when a stem that allows water to flow through the hydrant broke.

“So that put us in another mode to have to look for a secondary means of water supply,” Jackson said.

Firefighters did find a hydrant across the street and another at the far end of a nearby shopping center.

They knocked down most of the flames by 7:30 a.m. Redan Road reopened about 9:30 a.m., Jackson said.

Investigators have not determined what caused the fire.