Firefighters in the city just north of Montreal were called to a house on De La Chesnaye Street at 5:45 a.m. after neighbours said they saw flames coming out of the building.
Rescue crews found a man — identified as Jacques Dauphin — unconscious inside, and he was declared dead on arrival at hospital.
Police said the fire was intentionally set, meaning the death was most likely a murder or suicide.
"The circumstances surrounding Mr. Dauphin’s death are still unclear," said Cpt. SylvainThéorêt, spokesman for the Terrebonne–Sainte-Anne-des-Plaines–Bois-des-Filion intermunicipal police service.
"It wasn’t an accidental fire."
Théorêt said forensic teams have been working with the Sûreté du Québec since Friday to determine the exact cause of the fire.
Théorêt said Dauphin was not previously known to police.