Isn't there a thing you can plug into the wall that lets out an aultra sonic sound to drive away unwanted creatures....that we cant hear, but bugs and rodents can?
If you have some teatree oil spray some in the areas where you've seem them. Bugs definitely hate this smell and supposedly rodents do as well.
Hopefully,someone will chime in on the teatree efficacy on vermin. If it does work repelling them.