MONTREAL -- Hoaxes such as the one that led to a massive, hours-long police operation outside Ubisoft Montreal's Mile-End offices on Friday pose a major challenge for first responders, according to experts.

While rumours ran rampant on social media as police closed off streets and ambulances idled outside the video game company's facility, internet security expert Steve Waterhouse says it now appears the incident was a case of a phenomenon called “swatting.”

“Somebody is making a prank call and making that prank towards emergency services,” he explained. “Putting that emergency call to 911 and saying there's a hostage situation.”

The prank was anything but harmless, as dozens of people hid and sought shelter after receiving a message from building security telling them to “barricade yourself in a secure area that locks, place your phone on silent, remain quiet and hidden.”

Waterhouse noted that swatting has turned deadly on occasion.

“In 2015 in the United States, because of that kind of prank call, two people died,” he said. “The police officers went on site, everything went haywire and two people got shot.”

Nobody was injured during Friday's incident. Mayor Valerie Plante thanked police for their handling of the situation.

“I want to thank them, by the way, because they were really efficient yesterday,” she said. “It's something we didn't experience so much in Montreal so far, but we have to be ready and that's exactly what they did yesterday.”

While an investigation is underway, Waterhouse said tracking the source of the 911 call could be difficult due to computer programs that misdirect location data online. However, other swatting suspects have been located in the past. In 2014, an Ottawa teen was arrested for his role in a swatting prank and was charged with public mischief, mischief to property, uttering death threats and conveying false information with intent to alarm.

“He really thought he was above and beyond and the police services, with help from the FBI in this case, were able to track him down to his IP address in Ottawa and put handcuffs on him and give him his day in (court),” said Waterhouse.