PORTAPIQUE, Nova Scotia/OTTAWA (Reuters) - The death toll from the worst mass shooting in Canadian history rose to 19, including a police officer and the gunman, Canadian police said on Monday, adding that they expected to uncover more fatalities from the weekend massacre in Nova Scotia.

The gunman, who at one point masqueraded as a policeman and also painstakingly disguised his car to look like a police cruiser, shattered the peace of rural communities in the Atlantic province during a 12-hour rampage that started late on Saturday, authorities said on Sunday.

“We’re relatively confident we’ve identified all the crime scenes,” Nova Scotia RCMP Chief Superintendent Chris Leather told reporters on Monday, but said that fires set at some of those sites, mostly residences, made the search for other victims difficult.

“We believe there may be victims still within the remains of those homes which burnt to the ground,” Leather said.

The Royal Canadian Mounted Police identified the gunman as 51-year-old Gabriel Wortman, who worked as a denturist. Police said they had yet to determine a motive.

Police said on Sunday they had ended the threat posed by Wortman, who was dead, but they would not confirm a report by the CTV network that the RCMP had shot him.

RCMP Commissioner Brenda Lucki told the Canadian Broadcasting Corp on Sunday there was no indication at that time that the killings were terrorism-related. Police also said there was no apparent link between Wortman and at least some of his victims.

Lucki told reporters on Monday the investigation was going to be very long and complicated, adding the suspect was not well-known to police.

Leather said the suspect’s ability to move around the province was “greatly benefited” by the fact that he had a vehicle that looked identical in every way to a marked police car and that he was wearing a police uniform that was either a very good fabrication or an actual uniform.

Earlier, Canadian Prime Minister Justin Trudeau told reporters: A gunman claimed the lives of at least 18 people, among them a woman in uniform whose job it is to protect lives even if it endangers her own.”

He was referring to veteran RCMP Constable Heidi Stevenson, who was killed in the shooting spree on Sunday. She was a mother of two.

Another RCMP officer was wounded and was recovering at home, the police union said.

Trudeau said the killings “happened in small towns: Portapique, Truro, Milford and Enfield, places where people have deep roots, places where people know their neighbors and look out for one another.”

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“Now these communities are in mourning and Canada is in mourning with them,” Trudeau said.