The car was reported stolen in Laval yesterday and discovered later in the evening in Routhierville, in the Lower-Saint-Laurent region.
Police responded to a call around 7:30 p.m. and found the body of a woman inside the car.
Once they set up a perimeter and searched the vehicle, officers found a second body — a child under the age of 10 — in the trunk.
The police won't confirm the causes of death or how the woman and child were related.
Sûreté du Quebec spokesman Gregory Gomez Del Prado said the same vehicle was involved in a hit and run on the same day, around 6:30 p.m.
The car is a Dodge Shadow, model year 1994.
Police are asking anyone with more information about the vehicle and its whereabouts leading up to the incident to phone 1-800-659-4264.