Now that evidence has been scraped off the rubble from Saturday’s massive fire in Central Hamilton, police are interviewing witnesses while tests are run to see if they’re dealing with an arson case.

“It has not been an easy scene to work through,” Det. Sgt. Glenn Jarvie told CBC Hamilton. “This thing gutted the building. It caused a great amount of damage.”

Jarvie can’t yet say if police are dealing with a confirmed case of arson, though the fire is being treated as suspicious. “Every fire is treated as suspicious until it’s proven otherwise,” he said. “But we can’t determine if it’s an arson or not until we get tests back.”

And that could take some time. Officials from the fire marshal’s office have spent recent days scraping together samples from different materials within the burned out husk of the building – from burn patterns to carpet and pieces of wood.

Hamilton autobody shop fire

Shop owner Saber al-Taher says as many as 160 cars were damaged by the fire. (Sunnie Huang/CBC)

Those samples have been sent to the Centre of Forensic Sciences so investigators can figure out if an accelerent like gas was used to light the fire. Those tests can take up to 40 days to come back, Jarvie said. In the meantime, police are interviewing witnesses who saw the three-alarm fire rip through the industrial complex on Princess Street Saturday.

The fire was so intense that it sent fireballs into the night sky and producing smoke that affected residents from as far as the Mountain area. Several cylinders with flammable liquids inside the building exploded. Firefighters also dealt with several car fires. The building is about 100 years old and houses several autobody businesses.

At the height of the fire, there were about 75 firefighters and 24 fire trucks at the scene.  Some firefighters were treated for heat exhaustion. No other injuries were reported.

Saber al-Taher, who said he owns the building and one of the shops in it, said about 160 cars in his shop were wrecked by the fire.

"There's nothing left. Just the sign," he said.