I know this isn't good advice for anyone and I'm not giving it out, but I had a similar incident happen to me. Also in a home made ground blind that I have taken deer, coyote, and many turkey from. My neighbor's daughter's live in...sperm donor of her grandchild whatever you want to call him sat in my blind one day while I wasn't there.
I found cigarette butts, empty 12ga. hulls, and candy wrappers all around inside my blind area. He has no permission to hunt where this blind is, nor did he have permission to hunt out of my blind.
So I called him out by scratching a note in the mud with a stick where his feet were. I purposely tried to instigate a confrontation, but he didn't persue it. Now when he sees me he just glares at me. I know he saw it and could read it very clear, but he now avoids me.
I know it wasn't the right thing to do, and it wasn't the Christian thing to do, but I am a sinner and I lost my cool. I just wish he would man up and say something to me about it.
The property doesn't belong to me or otherwise I would run him out of there, but the landowner is 70+ yrs. old and he won't do anything about it....probably out of fear of retaliation from the slob who helped himself to my blind?
I feel your pain Tom I really do, but when your hands are tied......what else can you do?
I got my stuff out and never went back there. I now have a better place to hunt and I don't have to share ground with slob boy.