Corben, there's not much you can do other than maybe mentioning your concerns to a police officer; that, and setting up some illumination for your back yard.

Not to derail this thread, but I just read a post in another thread in which you describe your daily routine in caring for your invalid wife. My sympathy goes out to both of you. People who are physically incapacitated to a greater or lesser degree sometimes tend to withdraw from the outer world, and that can be a mistake. Maybe your wife should try to get more involved with her current friends and/or look up some old friends.