Credits: CARMINE MARINELLI/QMI AGENCY
The tragic shooting happened inside a home about 6 p.m., but it's not known where the gun came from.
The mother of the teens, who wasn't home at the time of the shooting, was taken to hospital suffering from shock once she learned of her son's death.
"The victim was hit in the head," said Stephen Smith, chief of operations for emergency health.
"The young man was in cardiac arrest while being transported by ambulance to the hospital."
The victim, who was shot at close range, was pronounced dead soon after arriving at hospital.
Police took his younger brother, who is reported to have called 911 after the shooting, to a Montreal station for questioning.
A neighbour of the family was visibly shaken by the events and said the boys "were not troublemakers."
"They were very nice and polite," she said. "I cannot believe it. This is a terrible tragedy."
Police remained on the scene late Monday and had cordoned off the area.