It wasn't clear what led to a tragedy in Mont-Saint-Hilaire in the Montéregie.
A 43-year old man is dead after he was hit by a car driven by his mother on Saturday night.
The 83-year old woman was trying to park the vehicle at the entrance of the man's home while he was monitoring her.
That's when she backed up and the vehicle ran him over.
The victim's six-year old girl witnessed what happened.
Police believe the woman may have stepped on the accelerator instead of braking, or there may have been a mechanical problem.
Members of the man's family, which was gathering for Christmas eve, were hospitalized for shock.
Authorities are investigating the incident.