Call the guy up, disguise your voice,
he said that he does not speak Polish. might this not rather give the game away?
it is infuriating.
short of poisoning the dog, there is not much else you can do I am afraid.
however if you kill the dog, the owner will just get another one so you are in the same position as you are at the moment
I have one alternative which will not result in the death of the dog nor any physical injury to the owner or his propery but you will have to PM me for details as I will not discuss this on a public forum
what gets on my nerves is when you have yuppies who move out to houses around cities and let their dogs out to roam around the fields until they come home from work. you end up with packs of dogs running around the countryside completely unchecked.