A gunman armed with a long rifle opened fire at a Montreal hotel on Monday, killing a police officer before being shot dead by responding officers, authorities said. A civilian was also killed, though investigators have not yet determined whose gunfire caused that death.Montreal Police Chief Fady Dagher said a second officer was seriously wounded but remains in stable condition following the shooting in the city’s Côte-des-Neiges neighborhood.Dagher noted that it was the first time in 24 years that a Montreal police officer had been killed while on duty. “It’s a very, very sad day. It’s a nightmare,” he told reporters.According to Dagher, emergency services received a call at about 11:35 a.m. reporting that a person was pointing a firearm out of a window at the Hilton hotel.Emergency services received a call at about 11:35 a.m. reporting that a person was pointing a firearm out of a window at the Hilton hotel (Reuters/Peter McCabe)Police arrived at the scene and were targeted with gunfire, he said. Video showed the shooter was also outside the hotel. Police are still trying to determine the suspect’s motive.Dagher said he didn’t know who shot the civilian.Jacob Coutu, who was working in construction near the shooting, said he heard “four of five gunshots” on Monday morning. A few minutes later, he said police officers started arriving at the scene in large numbers, and he heard more gunfire.“We saw cops getting in a gunfight, getting shot down,” Coutu said. He estimates he heard 30 or 40 gunshots.Public safety officials issued an emergency alert about an armed and dangerous suspect in the area, asking residents to shelter in place. The alert triggered temporary closures along a major highway, the Décarie expressway, as well as a temporary shutdown of significant sections of two subway lines.Dagher confirmed the suspect was dead before authorities issued the alert. Authorities eventually lifted the alert shortly after 3 p.m.