you might want to try to have a conversation with a local cop about what they would need to see in order to actually do something. like, is there any way to convince them that it actually is meth. maybe bringing in large quantities of certain chemicals or something. you may be able to capture this with some hidden security camera.

in the meantime, do you have access to the basement? you can put some plastic all along the walls and floor to try to stop the smell from getting into your house.

I wish I could be more help.