MagicPenguin
One Thousand Club
But I do believe that would be quite difficult. If it was intentional then the perpetrator may have had the support of a really really strong person otherwise they wouldn't escape the eyes and eyes of Albert and the rest of the powerful people in Blackrock.
the idea of it being done late at night is to avoid eyes and ears of anyone. The fact that guards or other witnesses didn't spot anything out of the ordinary before the fire may itself be a clue.
At least, that's how I was thinking of it.