Montreal police are searching for three people believed to have started a fire in LaSalle that left a 61-year-old woman dead.

Montreal Fire Chief Benoit Martel said the fire started on the backyard stairs of the central unit in the row of houses on Bois des Caryers St., near Angrignon Park, and could not be stopped from spreading to the adjoining units.

Someone called 9-1-1 at 10:30 p.m. to report the fire, but because of the proximity of other buildings, and with embers landing in the park, about 160 firefighters were called to battle the flames.

“I’ve never seen a fire like that,” said Di Feng, who has to evacuate his home with his two babies. “The fire sparks were everywhere in the sky and it was falling down on my grass and terrace.”

As people from the neigbourhood gathered to watch the flames, firefighters urged them to stand back and not interfere with their work.

Most of the residents of the homes managed to escape safely but have lost all their belongings. The Red Cross will provide care and shelter for those families, "about 15 to 20 people," for several days.

One resident told police that he did not think his mother was able to get out of the building on her own, and once the fire was extinguished a body was found in the wreckage.

Martel said he is certain that the body found is that of the missing woman, but an autopsy will be needed to confirm her identity.

“It's a tragedy,” said Feng.

Her death is considered the 9th homicide of the year on Montreal police territory.

Meanwhile firefighters said the location of the flames, and the fact the housing development is new, were signs the fire was deliberately set.

"In this part of the city all the buildings are brand new, since two or three years, so it's not supposed to be an electric fire. Maybe it can happen, but we just suspect other things," said Martel.

The arson squad and Montreal's major crimes division are now investigating the cause of the fire, with Montreal police saying that at least three people were seen running away from the building just before the fire began.

“Just before the fire started on the building, three people were seen leaving the scene behind the building,” said Montreal police spokesperson Julien Levesque.

Police say they haven’t been able to identify the arsonists but say witnesses gave them a description and there are security cameras in the area.

After the sun came up on Wednesday demolition crews moved in and began knocking down the bricks and other materials that were still standing.

Feng said he was relieved he and his children were able to escape.

“The entire basement is flooded but it's okay,” he said.

Damage to the buildings is estimated at $2 million.

The arson squad and coroner are investigating. Police say whoever set the fire could be charged with murder.