Mice only move at night. It is easy to decide if this is what you have because you will only hear scratching!!!!! You will not hear any running, walking, or movement. Mice will pick one spot to do their scratching and in some cases two spots. I know you are mouthing the words (no this is not a mouse I am hearing It's to loud). You will always hear a raccoon walking. You will always hear a squirrel running. You can't hear a mouse run or walk because it does not weigh enough.
We can solve most mouse cases in a two week period. Solving a mouse problem is done by two steps. Step one: Remove the mice. Step two: Close the entry holes. Why do the first step without the second step?