The heaviest thing in the room by default is the hardest to move, and thereby the hardest to place back. A small object from a desk would be easy to retrieve.
What I'm saying is that it could have been moved for annoyance purposes, of course.
[ Even if it was moved just to peeve this man, it doesn't make it less of a crime. And it makes perfect logistical sense and anyone who can't see isn't thinking properly. ]