Leave a note on his stand and tell him not to shoot any deer over the property line. Recheck your boundries make sure you know where they are. Make sure the boundry is clearly marked. I had a similar problem this year with a guy. He had two stands on my GF's Dad's property where we hunt. One was about 50 yards over the line and the other looked to be right on the line. I left notes in plastic bags on the stands signed by the landowner and sent one to his house. He called me up cussing me out and told me he was leaving the stand on the line. 5 minutes later his Dad called me saying the same thing. I went down to the spot, found the property stakes and marked them with ribbons, after finding the iron stakes his stand was about 5 yards over the line. He then talked to his landowner that gave him permission, and they had it surveyed. Yup he is 5 yards over the line. Still not happy the guy goes to see my girl's Dad who owns the property and he told him to move it. He just now agreed to move the stand. I think he will only move it far enough to be off the property, but still be shooting on our property, but I will be watching. He only has about 1 acre of woods and 2 acres of field to hunt, this guy is a jerk and should give it up.