We did not sleep very well last night. Here is the reason.
To solve this problem we got a bunch of traps (the humane kind that catch but don't kill) in the middle of the night and set them up. We have caught zero so far. Hopefully we chased it away. We found out how it had got into the house and we sealed it off very well (hopefully). The little bugger had chewed a hole in a corner in our back wall and snuck in. Good thing I am a freezer-a-holic and I put almost everything in the freezer. It only got into two pretzel bags (both where new but now are garbage) and a mostly empty bag of potatoes (also garbage). I freaked out over the whole incident. I spent multiple hours purging and bleaching our house today. I really hope this whole mouse in house incident is over. Yuck!