You can take it to a veterinarian to check if it's identified. 

If it's identified, the veterinarian will try to contact the owners.

You can report it to the municipal police.

If you can't find the owners and it's not microchipped, you can keep it while trying to find its owner. Put up ads in veterinary clinics, on social media, at local businesses, in WhatsApp groups...

If you can't find the owner, you can adopt the dog and have it identified in your name, vaccinated, and neutered to prevent reproduction. Alternatively, you can offer it for adoption on social media. We advise ensuring that it's placed with caring individuals. Follow up, regularly check on its well-being for a period of time...

You can also take it to the pound, but since the pound is overwhelmed with abandoned or unidentified dogs, the dog you drop off will likely be euthanized, like hundreds of others each month. 

You won't be able to drop it off at the shelter because we don't have authorization to take in unidentified and non-rabies vaccinated dogs.