A policewoman dragged the two bodies out of the water after a passerby noticed the bodies floating in the water.
Cpt. Yanick Parent of the Richelieu-St-Laurent police force said the victims appear to be in their late 70s or early 80s.
Investigators are still on site trying to find out more about the two people and how they ended up in the river.
“For now, we just consider the event like a suspect event… Everything will be explored,” Parent said.