Where do I report a police on my property, no was one home and there was no record of call?

I live in a jurisdiction outside of city limits. County Sheriff has jurisdiction. A city police officer working on the side as a private investigator was on my property looking around while off duty. I have video surveillance of him pulling onto my property in his police car when no one was home. No police had been called. Where do I go to report this? It has caused some serious damages to my case that he was investigating (privately) for the other side.