I'm hunting a new piece of land and the landowner says they have problems with trespassers. I have no experience with that situation so here is my question.

Let's say I'm a quarter mile from a road and encounter a trespasser. How do I handle the situation? I know to call DNR but what if the trespasser hauls ass? What proof do I need? Those are the type questions I have. Explain to ol Lab what to do please. Thanks for pardoning my apparent ignorance.