This is defintely a problem that has been discussed on other forums I visit. The one thing that one should never do is confront the culprit for numerous reasons. Best bet is to, as stated by the other response, is the trail cam idea. If you don’t have No Trespassing Signs posted, it wouldn’t be a bad idea to do so. It’s cheap insurance. You do have every right to protect yourself and your property and all that is in it. Just don’t delibrately set up a trap or anything that could potentially do physical harm to that person with the possibility of getting sued. It’s a terrible feeling that you have been violated and even more worse that we as land owners can’t handle these type of situations in this day and age. Best of luck to you.