Violation of the International Law?
When you are abroad and experience organized stalking, it could be a violation of International Law. The foreign county must have proper respect of your citizenship of your nation and your rights to be legally sojourn in their nation. In other words, if you are legally staying in the foreign country, the country and the government officials also respect you as a foreigner. Unfortunately, not all the nations on earth are safe for traveling or business. Some developing countries do have smugglers and illegal substance manufactures. Other places may have street mafias and organized crime groups. However, when you experience an organized-type crime organization when you are abroad in a country which is categorized as 'relatively safe,' things is different.
First of all, you must report their suspicious activities to the authority of that country. Also, you might want to report it to the authority of your own country for the safety of other travelers from your nation.
Second, you might want to discuss the case with other people who are expert in International Law or that country. This might change their category of the nation from 'relatively safe' to 'average,' yet this might be beneficial for other travelers attempting to visit the country.
Third, spread your experience. You might know about Colombian drug dealers and mafias. You might know about Indian street kids trying to sell junks to the travelers. Where these knowledge came from? You have read these things on media before and that make you to have a general image of these countries. If so, why don't you share your experience with others to make them aware of gang stalkers in the country you visited.
Damaging their country's image will be worse than owning a well-organized 'national security civilian units.' They sometimes cheats the victims, you know? They commit crimes if they see their victim cannot do anything to them. I am talking about gang stalkers in Holland here. Gang stalkers in Holland love stealing. This is from my experience. So, why don't you share yours?