Police divers found the baby’s body late Monday morning in Rivière des Mille Îles after the child’s mother’s vehicle plunged into the water last Friday afternoon.
The 40-year-old mother and a second child survived the incident, but the woman’s newborn boy had been missing for the past three days.
Police have so far been unable to speak to the mother because of her condition, Laval police spokeswoman Geneviève Major said.  The police investigation is still ongoing. 
The mother is recovering in hospital in a critical condition from the incident, while the other child, a four-year-old girl, has been released from hospital under the care of her father.
The tragic discovery comes after the third day of a search by police and fire crews in the river, which was interrupted twice on Friday night and Saturday as officers ran out of daylight.  The 42 km long Mille Iles River separates Laval from the North Shore.
Some local residents felt compelled to join the desperate search for the boy, as dive teams scoured the waters.
Police have not said how the mother’s vehicle ran off the road, and there are also unanswered questions about whether or not the baby was in a car seat.
This is a developing story.  More to come.