K.I.
Maybe she wanted stuff that reminded her of her great grandmother? I am not condoning her actions...just looking at the possible "why" of it all?
If this is totally out of character for her I would want to get to the bottom of the "why" of it all...but please remember at this age kids don't always know why they do the things they do...just keep calm, you are lucky you have been given all this time to reflect and come up with a game plan!