Quebec provincial police say a 48-year-old woman was attacked with a sharp object in what was described as an incident of domestic violence in the parking lot of Hôtel-Dieu long-term care facility.
The woman was at the hospital to receive treatment at the outpatient centre when she was attacked by a former boyfriend, police said.
The woman and the suspect had been living together until a few days earlier, said Sgt. Claude Denis.
The victim was found suffering from critical injuries in a vehicle in the parking lot just after 3 p.m.
She was transported to a different hospital and remains in intensive care.
"A few seconds after the assault, the suspect, a man, left the parking lot in a vehicle, this man had a collision with an overpass on Highway 20," said Denis.
Police said the 55-year-old man intentionally crashed his vehicle.
He was transported to hospital in critical condition, but died several hours later.