I won!
In the late night/early morning of playing mouse catcher. Harley and Shait did a great job of flushing the little guy out, and I caught him before too much harm was done and let him out the door. (I just can't kill them) But before I woke up I was dreaming about him jumping up and down in defiance of being caught. He was found the night before under the fridge. This is only the second time in their lives the cats have encountered live little critters. My apartment is on the first floor, and of course, it's getting cold out so they are seeking warmth. I have no clue where he came from. There is no sound coming from the walls.