Obviously, we don't have a lot of details.

For instance:

1) Why did he do this?

2) Did you ask him?

3) Do you have bad blood with him?

Some more background would be useful to give better advice.

Also, whatever you do, you may still have to live next to this neighbor for the long haul.

I'd consult with a good attorney.

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."