I used to get that same look when I would come home. That look of ‘Sorry, I didn’t mean to do it!” and could… sometimes.. never find anything.
You know what I discovered it was? They wake from a dream. They were doing something in a dream and when they woke up, they see me and think it was actually something they had done. I would always just forgive them, say it is alright, give them a hug and move on.
That was with only one dog. If TWO were giving me that look... I would spend time looking around more!