(CNN) -- In a country often stereotyped for being too genteel, the Canadian city of Moncton prides itself on a special distinction: It was named the most polite.
So what happened here Wednesday seems unimaginable to residents.
A man dressed in fatigues and carrying a rifle went on a rampage, killing three police officers and wounding two others.
Thursday morning, the shooter was still on the loose.
Residents were asked to keep their doors locked and their outside lights on, as helicopters hovered overhead and the hunt for the gunman continued.
Police say they know who the suspect is: 24-year-old Justin Bourque of Moncton.
What they don't know -- or haven't disclosed -- is what prompted the attacks.
Terror outside the window
The rampage began Wednesday evening when police responded to a report of an armed man in the north end of Moncton.
The gunman opened fire.
Three Royal Canadian Mounted Police officers were shot and killed, Constable Damien Theriault told reporters.
"Two of our officers were also injured, but their lives are not threatened at this time," he said, his voice breaking at times.
Joan MacAlpine-Stiles recalled seeing the gunman when she opened a window.
"It was really warm in the house, so we opened up the windows in the family room and there he was going across through the back with this rifle on his shoulder," she told CNN partner CBC.
"I said, 'Oh my God, there he is with camouflage and the headband and a gun, and it looked like a bow he had with him, and I mean he was just through our backyard,'" she said.
After police arrived, neighbor Vanessa Bernatchez watched with a couple of others from a living room window. She uploaded a video of the confrontation to Facebook.
"He shot him. He shot the ... cop," a man in the video exclaims. "Call 911!"
Moncton, a city of about 100,000 people, is about 90 miles (150 kilometers) northeast of St. John.
The Canadian magazine "Chatelaine" has described Moncton as one of the best places to live and work in Canada, according to the city's website.
In addition, "Reader's Digest" recently named Moncton as the most polite city in all of Canada, the city said.
Such accolades seemed to matter little now.
As the hunt dragged into Thursday morning, police continued giving updates and warnings throughout the night.
"Shooter still believed to be in Pinehurst Subdiv. area of Moncton. Stay locked inside. Avoid area," the RCMP's New Brunswick office tweeted.
All entrances to the neighborhood where the attack took place were blocked off, city spokeswoman Isabelle LeBlanc said Wednesday night. Her husband had not been able to get home.
Even some buses were pulled off the road because out of concern for public safety, she said.
Hospital calls in more help
As the two injured officers were being treated for their wounds, a local hospital had to get reinforcements.
"We have called in extra staff and physicians at The Moncton Hospital to help deal with this situation," said John McGarry, president and CEO of Horizon Health Network.
"We are restricting visitors to those with critically ill family members, and ask all others to refrain from visiting at this time."
Searching while grieving
As police keep looking for the gunman, they must do so while grieving the deaths of their colleagues.
When asked how officers would push through, Theriault said "we are professional."
Moments later, he choked up and ended the press conference.