When fire crews arrived, they found heavy flames already coming from the roof of the building, Mounsey said. Firefighters tried to enter the building, but the flames were too intense, she said.
"We tried to make it an interior attack, and the fire had already grown too intense that we had to switch to an exterior attack," Mounsey said.
Two workers who were inside the building escaped before fire crews arrived, the fire department said in a news release. The two people were working inside the building when the fire started, the release said.
Firefighters had the blaze under control in about 30 minutes, but the building had heavy fire, smoke and water damage. Three firefighters reported minor injuries but did not require treatment, the release said.
Investigators believe one of the workers accidentally started the fire while using a heating device to remove a kitchen appliance, the release said.
Allen County building records show the former restaurant was scheduled to be gutted, leaving only the outer walls, said Dave Fuller, director of the Allen County Building Department. A Fort Wayne contractor, E&V Construction, obtained a permit Jan. 2 for the interior demolition, Fuller said.
The owner of the building is listed as GAA Investment, 3400 E. Coliseum Blvd., in online Allen County property tax records, but a phone number for the company was not available.
The News-Sentinel left a message with Azar Restaurants., which shares an address with GAA Investment, but the call had not been returned as of Tuesday evening.