Laval Police have a man under guard in hospital after he along with two other men was spotted trying to open the doors of parked cars on Île Paton in Laval.
When a patrol car pulled up the trio fled.
The suspect in custody tried to escape by jumping from a bridge into the Rivière-des-Prairies.
He was eventually fished out and taken to hospital to be treated for hypothermia.
His two accomplices remain at large.