there is a very good chance that your calking is not in the bathroom anymore. not sure where you live and how much winter has set in but in the evening look in warm places. by heating vents, fridge or anything else with a warm motor. another thing is get small cages and put mice(or wood shavings from a mouse cage, pet store) in for him/her to find. leave the cages along the walls rather then in the center of the room. this should all be done in the evening or night. let me know if you find him/her.