Six people were killed and five critically injured Sunday night in shooting at a mosque in Quebec City. Here’s a timeline of the police response:

— At 7:50 p.m., police receive several calls from the Centre Culturel Islamique de Quebec reporting that shots had been fired.

— Police quickly arrive on site and arrest one suspect.

— Officers go inside the mosque and realize there are many victims. The attack is considered a major incident. All available police staff in Quebec City, including canine units, are called in.

— Police set up a security perimeter around the site.

— At 8:10 p.m., a second suspect calls 911 asking to speak with investigators. He tells police he will wait for officers at an access road near the Ile-d’Orleans bridge.

— Police go to the meeting spot and arrest the suspect.

— More officers go to the mosque to provide support for those on scene. A command post is established.

— At 10 p.m., an RCMP national security task force is deployed.

— Security is increased at other mosques in the city as well as the Universite Laval campus.