PORTAPIQUE, N.S. -- Investigators are continuing to piece together one of Canada's deadliest mass killings, which saw a man who at one point donned a police uniform and drove a mock-up cruiser slay at least 18 people in northern Nova Scotia.

Chief Supt. Chris Leather told a news conference Monday that the crime scenes include five fires where it is feared additional bodies will be found inside burned homes.

That "speaks to why we don't have a final total, because we expect that to rise in the coming days," he said, adding that some victims knew the killer while others did not.

Investigators in central and northern Nova Scotia are trying to piece together one of Canada's deadliest mass killings. The shooter, identified as 51-year-old Gabriel Wortman, was killed Sunday after police intercepted him at a gas station in Enfield, N.S.

"We'll never have an opportunity to interview the subject," Leather said, "but we can say 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, and beyond that, he was wearing a police uniform, which was either a very good fabrication of, or actually a police uniform."

The victims of the weekend rampage include an RCMP officer, a teacher, two nurses, neighbours of the assailant and two correctional officers killed in their home over 50 kilometres away.

For family members who are grieving, the common question amid their anguish was what could have motivated the carnage.

Kelly Blair, 48, lost her beloved younger brother Greg, 45, and his wife Jamie, 40, when they were gunned down in their home in Portapique, N.S.

As with families of other victims, it seemed that normal life collapsed in an instant in the small, rural community overlooking Cobequid Bay.

For Blair, a couple she "did everything together with" -- from driving all-terrain vehicles to camping -- was suddenly gone, and her "brother and best friend" senselessly cut down.

"Why? It's just why?" she said during a brief telephone interview.

"I honestly don't really know what happened. They were both shot. That's all we know, we don't know why. We don't know," she said.

Meanwhile, after an excruciating day unable to contact her sister, niece and brother-in-law, Tammy Oliver-McCurdie learned Sunday evening that the family, neighbours of the killer, had been found dead in their Portapique home.

Jolene Oliver, who was turning 40 this year, her husband Aaron Tuck, 45, and their 17-year-old daughter had moved to the community after Tuck's father died a few years ago.

An emotional Oliver-McCurdie said it's a small comfort to know that the close trio died together.

"No matter how much thy went through in life, they always stayed together, and there were times that they had nothing," Oliver-McCurdie said in a phone call from Alberta.

In Portapique, most residents who knew the killer saw him as an affable, house-proud seasonal neighbour who loved spending time at his sprawling log-home.

Neighbour Nancy Hudson said she met him about 18 years ago when he bought the property on Portapique Beach Road, which is just a short walk from her home on Highway 2.

"He was very jovial," she said in an interview just outside her house. "But there is another side to Gabe. He had some issues, especially with his girlfriend."

Hudson said she and her husband used to socialize with the assailant and detected "some underlying issues that I think he had with his relationship. It was a red flag .... (What happened on the weekend) wasn't a surprise to some degree, but not to this extreme."

She said was obsessed with his girlfriend. "Just being jealous about things with her. I think that's where things got in the way .... She was a beautiful girl."

Portapique is home to about 100 residents, most of them living in modest homes along Highway 2 on the north shore of Cobequid Bay.

But while the first victims were discovered by RCMP there, his rampage continued across a swath of northern Nova Scotia.

Jody MacBurnie, a neighbour and close friend of Alanna Jenkins and Sean McLeod, correctional officers who were killed at their home on Hunter Road, in Wentworth, N.S., described a frightening morning on Sunday for residents of a rural road in the small town.

He said he saw RCMP cruisers rushing up the road, "then we came to find out their house was on fire."

Nova Scotia Teachers Union president Paul Wozney identified teacher Lisa McCully as one of the dead in a Facebook post. She taught at Debert Elementary School, about a 20-minute drive north of Portapique.

"9300 NSTU hearts are broken along with those of her colleagues and students at Debert Elementary, as well as her family and friends who knew her not only as a passionate teacher but as a shining love in their lives," he wrote.

Judy MacBurnie, the aunt of a Portapique couple gunned down in the community, said Greg and Jamie Blair were among those killed.

The couple ran a firm that provides service, sales and installation of natural gas and propane units in the area. MacBurnie said they had two small children who are being cared for by grandparents, and Greg Blair also has two older sons from an earlier relationship.

The Victorian Order of Nurses noted the deaths of nurses Heather O'Brien and Kristen Beaton.

"All of our frontline care providers are heroes. Yesterday, two of those heroes, Heather O'Brien and Kristen Beaton, were taken from their families, and from VON. We mourn their loss, and we mourn for their families," wrote Jo-Anne Poirier, president and chief executive of the agency.

Corrie Ellison, 42, of Truro, N.S., was remembered Monday as a thoughtful, kind friend who went out of his way to help others.

Richard Ellison, who lives in Portapique, confirmed Corrie had been at his home in the community, but he declined to comment further on how his son died.

Gina Goulet, a 54-year-old in Shubenacadie, N.S., battled cancer twice before her life was taken from her Sunday, her daughter Amelia Butler said.

Goulet worked as a denturist for 27 years, but Butler couldn't say whether she had encountered the shooter, who worked in the same field, professionally.

RCMP Const. Heidi Stevenson, a 23-year member of the force and mother of two, has been identified as the officer killed. A male officer suffered non-life threatening injuries.

Prime Minister Justin Trudeau paid tribute to Stevenson and the other victims Monday in the House of Commons.

"She was great police, she was a great mom. She embodied the values that built this country. Values like integrity, honesty, compassion," he said. "For her community, she paid the ultimate price and her service will never be forgotten."

He noted that like Stevenson, many other victims were serving their community. "A teacher, a nurse, a child's grandparent, a parent's child. Who has the words to ease our sorrow?" he asked.

Later Monday, the White House released a statement with President Donald Trump and First Lady Melania Trump sending their condolences to Canada.

"The United States and Canada share a special, enduring bond," the statement said. "As friends and neighbours, we will always stand with one another through our most trying times and greatest challenges."

Premier Stephen McNeil described the massacre as "one of the most senseless acts of violence in our province's history."

"I never imagined when I went to bed last night that I would wake up to the horrific news that an active shooter was on the loose in Nova Scotia," McNeil said in Halifax on Sunday.

Governor General Julie Payette released a video message Monday night.

"A tragedy of this scale is so rare in our country that is almost beyond our comprehension," she said. "It calls for more than simple words. It calls for tears. And for solidarity.

"We do not choose when hardship comes, but we can choose how we respond to it.

"More than ever, let us stay united in these hard times -- to reach out, be kind to one another and to care for those who need it."

This report by The Canadian Press was first published April 20, 2020.

-- With files from Keith Doucette, Holly McKenzie-Sutter and Adrina Bresge