Ontario is a territory where Catholic churches are regularly closed and sold due to the decline in the number of faithful.
Police said the fire started at the back of the building, on the river side. The cause of the fire, however, is still unknown.
A large part of the roof collapsed in the afternoon, despite efforts by firefighters to overcome the blaze.
On the 22nd of April, arsonists even shot at the volunteer firefighters who came to extinguish the fire.
The damage is estimated to be over one million euros (1,2 million USD)
A thirty-two-year-old suspect has been arrested.
Despite early attempts to extinguish the fire, the wooden altar was destroyed and a statue of the Virgin Mary was damaged.
The fire ravaged the building and completely destroyed the roof.
Unknown persons tried to set a Lutheran church on fire in Latvia. The vandals may face punishment in prison.