A gunman disguised as a policeman killed at least 18 people, including a female Royal Canadian Mounted Police (RCMP) officer, in the worst mass shooting in Canada’s modern history.
The 12-hour rampage started late on Saturday and ended with a car chase.
Police said the suspect shot people at different locations in Nova Scotia, many of them randomly. He was killed in a confrontation with police.
He was reported to have been driving what looked like a police car.
Canadian Prime Minister Justin Trudeau described the attack as “a tragedy”.
“Violence of any kind has no place in Canada. We stand with you and we grieve with you,” he said, addressing the nation on Monday.
Nova Scotia Premier Stephen McNeil told reporters this was “one of the most senseless acts of violence in our province’s history”.
What do we know about what happened?
At about 23:32 local time on Saturday (02:32 GMT on Sunday), the RCMP said officers were responding to a “firearms complaint” at a home in the small town of Portapique and advised residents to lock themselves indoors.
The officers found “several casualties” inside and outside the home, but did not find the suspect.
A neighbour told CBC News that he saw three properties were also on fire in the area at the time.
At 08:54 on Sunday, the RCMP said there was an “active shooter investigation” and that there were several victims. It identified the suspect as 51-year-old Gabriel Wortman, who owned three properties in Portapique.
RCMP officers continued pursuing Mr Wortman for hours, following a series of crime scenes that police said were “scattered across the province” and which they are still working to piece together.
Mr Wortman was later seen in the Glenholme and Debert areas, east of Portapique, driving what the appeared to be an RCMP vehicle and possibly wearing an RCMP uniform.
“There’s one difference between his car and our Royal Canadian Mounted Police vehicles: the car # [registration plate]. The suspect’s car is 28B11, behind rear passenger window. If you see 28B11, call 911 immediately,” the force tweeted.
Mr Wortman then changed cars and was seen driving southbound along on Highway 102 from the Brookfield area in a silver Chevrolet Tracker, according to the RCMP.
At 11:40, the RCMP said that Mr Wortman had been taken into custody.
It later emerged that he was killed after being intercepted by officers at a petrol station in Enfield, about 92km south of Portapique. Witnesses reported seeing a body lying on the ground.