The Ontario Fire Marshal is investigating after another suspicious fire at the former Mount Slaven Public School in Orillia.
The building on Westmount Drive has been vacant for nearly 10 years and has been the target of vandalism, squatting, break-ins and suspicious fires.
Investigators believe someone gained entry to the building overnight on Friday before the fire started because they found broken windows and say the building wasn't secure.
It took 16 firefighters and eight hours to battle the blaze.
"At one point, we stopped operations on the roof just because we were concerned about some of the structural damage," said Orillia Fire Chief Brent Thomas.
OPP forensic investigators and the OFM sifted through the mess inside, suggesting it could take weeks to determine what sparked the flames.
"The fire appears to be in the gymnasium, in the middle of the north east section of the school on the stage," said Ontario Fire Marshal James Allen.
Some neighbours we spoke with today said they would prefer the building to be torn down, calling it an eye sore.
"I'd like to see it demolished, because it's non-stop problems here. Kids, adults, drugs in and out, cops, fire department at five o'clock in the morning, the whole street awake," said resident Jason King.
The OPP is urging anyone with information to come forward.
Link to original article on barrie.ctvnews.ca: Another suspicious fire breaks out at an abandoned Orillia school