Marystown RCMP said three young men went inside the hotel, after one of the teens spotted smoke billowing from the building on Ville Marie Drive.
"The three teenagers then entered and went through the building at their own peril alerting those inside to the danger and ensured all were safely outside," an RCMP news release said.
By the time firefighters with the Marystown Fire Department got on the scene shortly after 1:00 a.m., everyone inside the hotel — which had rooms booked — were outside.
"When we checked the attic itself, we determined there was a large amount to heat so obviously it had been burning for a period of time. But rather than risk any life we came off the roof and concentrated our efforts on extinguishing the roof itself," Fire Chief Alex Coady told CBC News.
Police looking for witnesses
The hotel, which is believed to be approximately 20 years old, was completely engulfed by flames well into the early morning hours.
As the fire quickly spread, Coady said they turned their attention to nearby St. Gabriel's Hall, a historic building that sits about 12 feet from the hotel.
"So we started to concentrate our efforts on the far end of the roof line, trying to keep everything wet down and do what we could so that it didn't spread to the hall itself."
Members of the RCMP will remain at the scene of the destroyed building on Monday. The cause of the fire is still under investigation.