Knock Knock Who's There?

What a surprise we had when we walked into our classroom. A magical looking box with a locked door was in the classroom. We had great fun guessing what might be inside. Then, after lunch, we discovered the box in the hall and everything that had been inside had got out. They'd left an awful mess but it gave us some clues as to who might have been in the box. We became investigators to try to discover who it might have been.