The victim has been identified as Diane Lahaie, 64, the home's owner and fire was set on purpose, police say.
Emergency crews were called to a home at 14 Rue de Gaspé early on July 27 for a house fire.
Firefighters doused the blaze but a body was later found inside the home.
Forensic assessments are still ongoing.
Lahaie's death is Gatineau's third homicide of 2013.
Police had located a 2004 Pontiac Sunfire on the night of July 27 they called a vehicle of interest in the investigation. They have not released more information regarding that vehicle.