In the aftermath of a devastating Saturday night fire at 191 Grenfell Street that killed three people, fire investigators are getting closer to determining how it happened.

Meanwhile, the community is mourning the people it lost and celebrating its heroes.

"We know the fire started inside a room in the building," said fire Investigation Coordinator Rick Derstroff with the Ontario Fire Marshal office who was on the scene Monday.

"We're just now getting into that back room [where the fire started.]"

The investigation is also still trying to determine if a smoke alarm they found was working at the time of the fire.

Investigators expect to be there until late Monday or into Tuesday, he said.

Derstroff was able to confirm that they have no reason to suspect anything suspicious. He also said that the fire started inside of a room—that is, not inside of a wall or from any part of the exterior.

On an overcast Monday afternoon, the team of investigators sifting through debris is barely an echo of the emergency task force that descended on the sleepy street Saturday night. Firefighters were called to the home, near Kenilworth Avenue and Beach Road around 11:30 p.m. Saturday. When they arrived the home was fully engulfed in flames and neighbours were making desperate attempts to try to save the occupants.

Emergency workers swiftly extinguished the raging fire, but not before it killed three people who lived in the house. Two escaped, thanks to the efforts of the neighbours.

Those three who did not are being mourned today.

There has been no official release of the victim's names. But neighbours and friends identified the victims as: A 29-year-old male; a woman who lived there with her daughter, and an older man who they say was visually impaired.

Friends and neighbours describe the 29-year old as "the best neighbour ever."

His best friend, Joe Hatfield, is wracked with anguish. Hatfield said he's lost other loved ones in the last few years, "and this sure doesn't help." In the wake of the fire, Hatfield said he's the one who delivered the bad news to his friend's parents.

Sarah Ignacio, who lives across the road from 191 Grenfell, said the late 29-year-old was "the type of person who'd do anything for you." Ignacio is still shaken by the memory of seeing her neighbours' bodies in the street.

They say the two survivors, reportedly both still in hospital according to family and friends, are the man who owns the house, and the daughter of the woman who died. The surviving daughter jumped from a second-storey window at the front of the house, at the insistence of neighbour Jonathan Davidson who was there to break her fall.

"I think she's incredibly brave and strong," Davidson told the CBC on Monday. "She had to leave her mother behind and it takes incredible strength to do that."