They're doing the investigation today (it's 7 in the morning, so I don't know if they even started yet) but I'm gonna guess some idiot tried to use their fireplace.  The fire went right up the wall so I think the whole righthand side of the building is damaged (and I'm sure all that hose water trickled down and ruined all three condos).  We're probably going to have a fireplace ban, which we already should have had because they never get them cleaned out.