Hall County Fire Capt. Scott Cagle said the owners of the Professional V Twin, a motorcycle shop in the 2800 block of McEver Road, have received threats on their business in the past.

"We won’t get into who and why, but we are looking at every possible angle," Cagle said.

Callers to 911 reported hearing an explosion at the strip mall shortly before midnight Thursday. When firefighters arrived, they found the motorcycle shop engulfed in flames. Debris blown into the parking lot indicated an explosion had occurred, Cagle said.

Firefighters deemed the blaze too dangerous to enter the building and conducted a "defensive attack" on the structure. They spent more than two hours at the scene.

Because of heavy fire damage, investigators think the explosion may have occurred after the fire started.

No one was at the shop or the adjoining business, Totally Cabinets, at the time of the fire, Cagle said.

A firewall protected the cabinet shop from all but smoke and water damage, Cagle said.

The total value of the strip mall was $1.4 million, and the damage to the structure of motorcycle shop was estimated at $500,000, with another $300,000 in contents lost, Cagle said.

The shop owners, Philip Hall and Andy Sudderth, told fire officials that five motorcycles and an all-terrain vehicle were in the shop at the time of the fire, Cagle said.

Cagle said the building’s age — it was constructed just 18 months ago — tends to make investigators doubt that the fire was started by a natural gas leak.

"We received information that it may be suspicious," Cagle said.