VANCOUVER -- When a gunman killed three Mounties, wounded two others and then led police on a manhunt through Moncton, N.B., Twitter quickly emerged as one of the best sources for updates, both for residents of the city and for Canadians watching in horror from afar.
As the drama unfolded, the RCMP posted up-to-date information about where the alleged shooter was believed to be and -- more crucially -- what people living in those areas could to do keep themselves safe.
The force posted nearly three dozen updates during the 30-hour manhunt, finally restoring a relative sense of calm with just 131 characters.
"Justin Bourque arrested by RCMP at 12:10 in Moncton," the force wrote, referring to a man now facing murder and attempted murder charges, in a post that was retweeted 14,000 times.
"He is in police custody. Residents of north Moncton can now leave their homes."
It was an extraordinary example of how police forces across the country are using Twitter, whether they're offering real-time information during disasters, asking for tips or breaking news about arrests.
"During a live incident, they can be soliciting tips from the public and it's also a very immediate way to issue public orders, like: 'Don't come out of your house, there's an active shooter in the neighbourhood,"' says Christopher Schneider, a sociology professor with the University of British Columbia who has published a new study about how Canadian police forces are using the social media website.
"They can do it with traditional media, and they did, but when they do it on social media and Twitter ... the information shares a lot more quickly."
Schneider says police forces are flocking to Twitter, with forces in Toronto, Montreal and Vancouver each boasting tens of thousands of followers.
But he argues in his study that Twitter can both help and hurt. While the service offers a new way to interact directly with the public, it also presents potential risks as officers blur their professional and private lives.
Schneider examined more than 100,000 tweets from the Toronto police -- both on the force's official accounts and from officers.
Twitter was primarily used as a publicity tool, says Schneider, with the force and its officers using the service to highlight the good work of the police and develop a relationship with the public.
"I think it's a lot more about public relations, primarily about encouraging symbolic support and doing what the public expects of the police," he says.
"Using Twitter in this way to encourage (public confidence) is helpful."
On the other hand, Schneider says becoming too personal on Twitter -- which, for many users, is the entire point -- can become a problem, especially when individual officers are tweeting.
Schneider says officers are limited in what they can say about their actual work, for fear of releasing sensitive information, so many officers' accounts are peppered with non-work related material -- comments about a hockey game or a photo from a family vacation, for instance.
It might seem like a good idea to present an officer as a likable "average Jane," but Schneider says that could actually undermine the ability of officers to do their job if they encounter people who recognize them from Twitter. It's the same reason most forces don't allow beat cops to work in their own neighbourhoods, he says.
"When I'm speaking on behalf of myself and I'm also an officer, this personalizes these officers," he says.
"If these personalized officers then have to use their authority in the street by arresting people or ticketing people and there is a personal relationship, this has the potential to erode police legitimacy."
Schneider says it's also not clear whether officers who tweet on their own time are still representing the force.
For example, his study notes Ontario's Police Services Act prohibits officers from endorsing a political party or candidate while on duty, but it's not clear how that might apply if an officer is tweeting from home.
"Twitter is immediate, and police need to be very careful about what they say," says Schneider, whose review of Toronto police tweets doesn't identify any obvious examples of officers crossing the line.
There have been several cases in recent years in which officers or police forces ran into trouble because of online posts.
Last year, a police officer in Durham, Ont., was disciplined after using a fake Twitter account to attack the province's ombudsman, who was called a "carded member of al-Qaida."
A Mountie in Nanaimo, B.C., faced an internal review in 2010 after a series Facebook updates that included lewd comments about women he arrested.
In the United States, a police force in Maryland announced plans earlier this year to post live updates to Twitter during a prostitution bust, which prompted complaints that the stunt would shame women caught up in the sting. The force scrapped the plan.
