How can I stop a person from photographing or approaching my property?

Long story short, a person I am unfortunately related to has been practically stalking me. They have taken pictures of my property, sources say they have hired investigators to follow me and I feel like I have no privacy even at work. Strange cars have pulled up right behind me, just sit there, and leave! I know restraining orders can be done, but I don't want this person even near my property because I feel they will destroy something or harm my family when I'm gone. What can I do?