He was probably looking for his keys or something.
you usually don't crush a village to fins something within it.
He was masking as the Kazekage and snoop around the forest of death personally.If he was looking for something it would of been hinted at or mentioned by now.Besides what is more important then his goal that we all know of that he had to destroy the leaf ?
I am not trying to smite you down but i highly doubt it something that simple
As for me i have no clue what his true reason might be ........for now anyway.
I was so set in oro being pure evil and nothing more.Maybe there is more to him.
He is strongly motivated and we have had hints as to why he is the way he is.Maybe we will get more info on his past or inner feelings soon /: