The place wasn't too far from my office. The building itself was heritage listed so couldn't be touched. I'm guessing that, as it was abandoned, there was obviously no running electricity going into the building, the fire must've come from another fire WITHIN the building. Now, as squatters frequent abandoned buildings like that for shelter, they only need one thing - heat. I'm guessing that they brought a barrel into to the building and lit it up. Probably the bottom of the barrel started getting a little hot, even perhaps burnt through, and the floorboards in that building (that's what they were built like back then) went up, and that's all it took.