A denture-maker went on a rampage in a small town in Nova Scotia—killing at least 18 people, including a police officer, and sparking a 12-hour manhunt that ended with his death in a standoff at a gas station.

The Royal Canadian Mounted Police identified the suspect as 51-year-old Gabriel Wortman, who owns denture clinics in Dartmouth and Halifax, and who apparently dressed as a police officer as he sowed terror across 55 miles.

Authorities initially said he had killed 10 people, but the toll rose through the night as more victims were found, making it the deadliest attack in Canada’s history.

“This is one of the most senseless acts of violence in our province’s history,” Nova Scotia Premier Stephen McNeil said.

The orgy of violence began late Saturday night in rural Portapique, where Wortman has property, when officers responded to 911 calls about gunfire.

“When police arrived at the scene, member located several casualties inside and outside the home,” Chief Superintendent Chris Leather said at a news conference on Sunday evening. “They did not, however, locate the suspect.”

Police swarmed the area and began hunting for Wortman, who set several buildings on fire before leaving the quiet seaside town of 1,600 and heading toward the port city of Halifax.

“This was a very quickly evolving situation and a chaotic scene,” Leather said.

Wortman made his way through several towns over the course of Sunday morning, with police tweeting out warnings to residents by the hour.

At one point during his escape bid, police said it was possible Wortman was in a vehicle made to look like a police car and wearing a police uniform. An hour later they tweeted he was believed to be in a small silver SUV, suggesting he had switched vehicles.

Catherine Harrop was working in a cider bar in Elmsdale when police swept through looking for Wortman.

“Two of the armored SWAT vehicles pulled up out front, and a bunch of armed officers in camo got out,” Harrop told The Chronicle Herald. “Two of them came into the Sobeys [food market] and some of the others walked through the parking lot. The ones that came inside told everyone to go into lockdown, lock all the doors, turn off all the lights and stay away from the windows until they gave us the go-ahead to open up again.”

Police apparently cornered the suspect at the Irving gas station and Big Stop restaurant in Enfield. A truck driver there told CTV News he heard a gas station employee shouting.

“She goes, ‘Oh my God, lock the doors, he’s here!’ And I peek out of the window and I saw some RCMP vehicles and there was four or five uniforms with guns,” the driver said.

Another witness, Glen Hines, said, “All I could hear was gunshots and my wife, I thought I was going to call 911, because she was going into panic, it scared her so bad.”

Paula Hanrahan told The Chronicle Herald she was driving home when she saw the commotion.

“I could see the back end of a silver SUV and, oh my dear, there were more men than I could count in full gear with ‘police’ on the back and assault rifles in their hands,” Hanrahan said.

“All you could hear were the dogs growling, clawing at the pavement to get to this vehicle, and men yelling.”

Other witnesses said that after gunshot rang out, they saw a body on the ground.

Soon after, police said the suspect was “in custody.” CTV News reported that Wortman was killed.

Many details of the incident were still unclear, including what sparked the initial paroxysm of violence and why police believe Wortman was in a phony police car.

Assistant Commissioner Lee Bergerman identified the slain officer as Heidi Stevenson, a 23-year police veteran and mother of two, though he did not provide details about when and where she was shot.

“I met with Heidi’s family and there are no words to describe their pain,” Bergerman said.

“Countless families are in mourning today.”

Wortman has been in the news before. In 2014, he responded to a CTV story about a cancer survivor who lost her teeth and could not afford replacements. He offered to make new ones for free.

“My heart went out to her,” Wortman said then. “There’s so many ways for people to get dentures, but it seems like the people who really need them are the people who are getting left behind.”

TV host Candy Palmater told The Chronicle Herald that she and Wortman were close in college.

“I knew right from the beginning that this guy needed a friend, so I befriended him,” she said. “Most of my friends didn’t like him, but I didn’t care. He met my parents and members of my family, and we were inseparable for that whole year.

“I always felt like he wasn’t quite comfortable in his own skin, but I thought as he matured, he would grow into himself.”

She added, “Gabriel always had a sadness about him, but I was so shocked to hear that he’d hurt other people. I don’t know what his later adult life was like, but I can tell you that at university, people weren’t nice to him.

“He was a little bit different, like I’m a little bit different, but he was beautiful and he had a really deep heart, but he was the brunt of everybody’s jokes.”