First you need to identify the animal. Then we can recommend either trapping or some type of repellant. Try out the flashlight several times during the night. Of course it also depends on what you are willing and allowed by law to do.

The problem is that my garden is in another location - not my yard. I have asked the garden coordinator to set a trap for what I am told is a mole, a pest that is more common to the area. Now I will wait and see.

You could put a screen on underneath next year and hand pick get rid of your grubs.