She was one of two people critically injured in the fire, said Trevor Bain. She suffered severe burns to her upper torso and to her head. She was living by herself at the time.
The second victim, Nicole Beliar, succumbed to her injuries on Tuesday. She was 33.
Belair worked as child protection worker with the Children's Aid Society.
“The Children's Aid Society is in absolute mourning today,” said executive director Collette Prevost. “It's difficult to imagine that Nicole is gone.”
James Allen, fire investigator with the Office of the Fire Marshal, said Belair was visiting the 59-year-old victim at the time the fire started.
He would not confirm that Belair had re-entered the building to help someone, as has been reported by other media.
The apartment's resident provided a statement following the fire, but due to the severity of her injuries, she hasn't been able to speak to investigators since, Asunmaa said.
Now, Allen and his team are conducting an investigation into the origin and cause of the fire. He said the blaze started on the main floor of the building in the east section inside a kitchen area, spread west and up a staircase.
Witnesses at the scene reported hearing a bang prior to the fire, Allen said.
“A forensic engineer is looking at appliances (in the kitchen) as potential causes (of the fire),” Allen said. “The engineer is also looking at an oxygen tank inside the apartment, as well as the fridge.”
Police have ruled out any “criminality” through its investigation, said Staff Sgt. Al Asunmaa.