Police have fanned out across more than a dozen crime scenes after a rampage by a gunman disguised as a police officer left at least 18 dead and homes in smouldering ruins in rural communities across Nova Scotia — the deadliest mass shooting in Canada’s history.

Officials said the suspect, identified as 51-year-old Gabriel Wortman, also died in the weekend attack. Authorities did not provide a motive for the killings.

Royal Canadian Mounted Police Chief Superintendent Chris Leather told a news conference that officers expect to find more victims when they comb through all the crime scenes, some of which were houses set ablaze as victims were inside, adhering to government calls to stay at home because of the coronavirus pandemic.

Mr Leather said police teams were spread out at 16 locations across central and northern Nova Scotia. He said some of the victims knew Wortman and some did not.

“We’re relatively confident we’ve identified all the crime scenes,” he said. “We have had five structure fires, most of those being residences, and we believe there may be victims still within the remains of those homes which burnt to the ground.”

The dead included a policewoman, while another officer was wounded by gunfire and was recovering at home.

“The 18 innocent lives lost will be remembered throughout Canada’s history,” public safety minister Bill Blair said.

Prime minister Justin Trudeau noted how close-knit the small province of Nova Scotia is.

“The vast majority of Nova Scotians will have a direct link with one or more of the victims. The entire province and country is grieving right now as we come to grips with something that is unimaginable,” he told a news conference.

“The pandemic will prevent us from mourning together in person, but a vigil will be held virtually to celebrate the lives of the victims,” he added, saying it would take place on Friday night through a Facebook group.

Mr Trudeau asked the media to avoid mentioning the name of the assailant or showing his picture.

“Do not give this person the gift of infamy,” he said.

The 12-hour rampage began late on Saturday in the rural town of Portapique, about 60 miles north of Halifax, where police warned residents to lock their doors and stay in their basements as the attack unfolded.

The town, like all of Canada, had been adhering to government advice to remain at home because of the pandemic and most of the victims were inside when the attack began.

Several bodies were later found inside and outside one house on Portapique Beach Road, the street where the suspect lived, authorities said.

Bodies were also found at other locations within a 30-mile area of the neighbourhood where the shootings began, and authorities believe the gunman may have targeted his first victims but then began attacking randomly.

Canada Shooting
Royal Canadian Mounted Police officers were called to the petrol station (Tim Krochak/Canadian Press/AP)

Authorities said the gunman wore a police uniform and made his vehicle look like a RCMP patrol car.

“His ability to move around the province undetected was surely greatly benefited by the fact that he had a vehicle that looked identical in every way to a marked police car,” Mr Leather said, adding that the gunman was also either wearing a police uniform or a good copy.

He said at one point the suspect was forced to abandon his car and then carjacked other vehicles to continue to “circulate around the province steps ahead of our investigators”.

Authorities believe he acted alone. RCMP Commissioner Brenda Lucki said he was not well known to police and no note from the suspect had been found. She said police were still studying the crime scenes to determine what weapons were used.

According to his high school yearbook, Wortman long had a fascination with the Mounties. “Gabe’s future may including being an RCMP officer,” his yearbook profile said.

The dead officer was identified as Constable Heidi Stevenson, a mother of two and a 23-year veteran of the force.

Constable Heidi Stevenson
Constable Heidi Stevenson (RCMP/Canadian Press/AP)

Two health care workers at local nursing homes were also killed, according to Von Canada, a long-term health care company, which identified them as Kristen Beaton, a continuing care assistant, and Heather O’Brien, a licensed practical nurse.

Ms O’Brien’s daughter, Darcy Dobson, wrote in a Facebook post: “A Monster murdered my Mother.”

“Murdered her, without a second thought. The pain comes and goes in waves. I feel like I’m outside of my own body. This can’t be real. At 9:59 am she sent her last text message to our family group chat. By 10:15 she was gone.”

School teacher Lisa McCully, who worked at a local primary school, also was among the dead. “Our hearts are broken along with those of her colleagues and students at Debert Elementary,” Nova Scotia Teachers Union president President Paul Wozney said.

Wortman, who owned a denture practice in the city of Dartmouth, lived part-time in Portapique, according to residents.