Advice needed regarding a problem neighbor

[Daniel Hess]

I bought a house with a tenant a month later they left because the neighbor had started to harass them. They had a restraining order placed against him and put up security cameras. They had lived there for the last six years with the same neighbor, but never had a problem with him until recently and according to them with no reason. They left for fear that he would hurt them or thier children. So now I have a vacant house with a possibly dangerous guy next door. Anyone got some advice before I fix the house up and rent it again, is their anything I can do legally to keep him from harassing future tenants? Thanks