MONTREAL – Arson investigators have returned to the scene of a deadly fiere in St-Michel, while they await autopsy results to confirm the victim's identity.

The fire broke out around 11 a.m. Wednesday in a duplex on 15th Ave.

With a combination of bitter cold and intense flames and smoke, the fire spread quickly, forcing firefighters to work defensively.

β€œAt one point, we had to retreat,” said Montreal Fire Department fire chief Martin Farmer.

Once the fire was under control, firefighters performed an exhaustive search of the home.

They discovered someone unconscious in a room on the first floor toward the back of the house. Firefighters believe the blaze broke out on the first floor.

Firefighters said they were unsure if the fire alarms were installed and working properly in the home.

Police wouldn't confirm who was found inside, but neighbours said a family with four children lives in the residence and it may be a 19-year-old woman. Police wouldn't confirm if a woman is missing from the scene.

Firefighters are not yet able to confirm the cause of the fire, which did not spread to neighbouring buildings.

About eight to ten people evacuated to building and the buildings on either side of the home. Those residents were takin in by the Red Cross.

The Montreal police arson squad is investigating the fire, as is protocol when there is a death or serious injury. That does not necessarily indicate the fire is criminal.

Police, however, said investigators were not able to inspect the scene adequately Wednesday due to all the ice caused by extinguishing the flames.