The repeated attempts to burn down the building made headlines in Austria, and then went viral after it was posted online on Fark.com by a joker who noted a sarcastic conversation between two Austrian policemen.
Linking to the article in English, they wrote: "Officer Karl, someone's tried to set this building on fire five times in the last four days. Do you think we should do a stake-out, or something?" "Naw, I'm sure they won't... do you smell smoke?"
Police pledged to make sure it did not happen once more, but now despite adding extra patrols, it did happen again - twice.
First of all, on Sunday the roof of the property in the Gnigl district of Salzburg caught fire, filling the property with smoke and causing firemen to head to the scene to extinguish the blaze.
They left, but one hour later they were back again after a fire broke out again this time on the first floor.
There are six people living in flats in the property, who say they are afraid for their lives now. One told local media: "I don't understand who dislikes us so much, I have no idea why they are doing this."
Police spokesman Michael Rausch said that whoever had been starting the fires had not been using incendiary chemicals, and instead had simply been setting fire to clothing or other materials meaning it was difficult to test possible suspects for flammable liquid.
They believe it was one person who knows their way inside the property because they always seem to manage to open doors to otherwise empty rooms and gain access to areas like the roof or the cellar.
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The six previous fires had been started during the night-time in the cellar, the roof, and the hallway of the building.
Story courtesy of Central European News