Residents in Nova Scotia are struggling for answers after a lone shooter killed 16 people, including a police officer, in the deadliest rampage in modern Canadian history.

Royal Canadian Mounted Police said on Sunday that Gabriel Wortman, a 51-year-old denturist, had been taken into custody but was later pronounced dead following a standoff at a gas station near the capital of Halifax.

It was not clear how Wortman died but police later issued a statement saying that Nova Scotia’s serious incident response team said it was investigating an event in which RCMP officers “discharg[ed] their firearms” at a suspect.

An undated photograph released by police of Canada shooting suspect Gabriel Wortman. Photograph: Royal Canadian Mounted Police/AFP via Getty Images

According to property records, Wortman owned and operated a denture clinic in the city of Dartmouth, across the water from Halifax. In 2014, he appeared in local media after donating dentures to a cancer survivor.

Neighbours of Wortman, who owned three properties in Portapique, a small coastal community where the rampage appears to have begun on Saturday night, were shocked by the news.

“Very, very shocked to think that someone we’ve known for so long, a good neighbour, a helpful neighbour, very kind, would ever think of doing such a tragedy,” Lillian MacCormack told CTV News.

“We never know what others go through in life that makes them make certain decisions,” Scott Balser, a former classmate of Wortman, wrote on Facebook. “I am by no means defending his actions this weekend.”

David George Crockett told the Toronto Sun that Wortman had once fixed his teeth at his home in Portapique.

“I’m very surprised,” Crockett said in a brief interview. “I never thought he would do something like that.

“From what I knew of him, he was quiet, gentle and very easy to talk to …. He was very nice. He kidded around a little bit. He seemed normal, not like someone who would do something like this.”

Tom Taggart, a lawmaker who represents the Portapique area in the municipality of Colchester, told the CBA he did not know Wortman well, but spoke to him a few times when he telephoned about municipal issues. He described knowing Wortman’s “lovely big home” in Portapique. He said Wortman owned a few other properties and was believed to divide his time between Portapique and his business in Dartmouth.

A photograph of his high school year book said his future “may include being an RCMP officer”.

Police have not yet determined a clear motive for the shootings, but suggested the killings had a degree of premeditation and that Wortman acted alone.

“I believe at the beginning there was an initial motivation and then I think it turned to randomness,” RCMP commissioner Brenda Lucki said on Sunday evening. “We don’t know for sure and we’re going to have to do a lot of work on finding the motivation ... a lot of background, profiling type of events and a lot of crime scene processing.”

She also said that police did not believe the incident was terror-related.

One unusual detail was that Wortman was disguised as a police officer and had mocked up a car to make it look like a police vehicle. On Sunday morning, police in Nova Scotia tweeted out an image of the car that Wortman was believed to be using.

#Colchester: Gabriel Wortman may be driving what appears to be an RCMP vehicle & may be wearing an RCMP uniform. There's 1 difference btwn his car and our RCMP vehicles: the car #. The suspect's car is 28B11, behind rear passenger window. If you see 28B11 call 911 immediately. pic.twitter.com/yyeOeBt8Ui — RCMP, Nova Scotia (@RCMPNS) April 19, 2020

“The fact that this individual had a uniform and a police car at his disposal certainly speaks to it not being a random act,” RCMP Chief Superintendent Chris Leather said, adding that Wortman did not appear to know a number of the victims. On Sunday evening, police confirmed that constable Heidi Stevenson, a 23-year veteran of the force, was among the victims.

With the province already in lockdown in order to contain the spread of the coronavirus, police said the community would be hit hard by the attack.

“What has unfolded overnight and into this morning is incomprehensible and many families are experiencing the loss of a loved one,” said commanding RCMP officer Lee Bergman.

Statement from Nova Scotia RCMP Commanding Officer, Assistant Commissioner Lee Bergerman https://t.co/mV9IcRqe2B pic.twitter.com/yRaL8F8EdS — RCMP, Nova Scotia (@RCMPNS) April 19, 2020

According to police, Wortman’s rampage began shortly before midnight on Saturday in Portapique, culminating in a manhunt that lasted for more than 12 hours.

Residents heard gunfire and began to see police gathering on the streets. They were then told to lock their doors and seek shelter in their basements.

One woman said she had come across two burning police vehicles while out driving on Sunday morning. One man said he saw at least three separate fires but police did not confirm if the fires were related to Wortman.

“There was one officer we could see on scene and then all of a sudden, he went running toward one of the burning vehicles,” Darcy Sack told the CBC.

“We heard gunshots,” she said, adding that one police officer looked to have been injured.

Following a chase along a busy highway, Wortman was apprehended around midday at a gas station in Enfield just outside the city of Halifax.

Lisa and Laurie George, both residents of Portapique, told Global News in Halifax that at approximately 11pm on Saturday they saw flames nearby, eventually seeing three separate fires in the area.

The couple said that a large group of police quickly arrived in response, followed by gunshots before RCMP told them to go home.

Another neighbour told the Toronto Sun that he and Wortman had been friends until they fell out over a piece of property.

The neighbour, who declined to give his name, said Wortman had burned an old shed that contained some property that belonged to the neighbour but declined to give any further details of the dispute.