Who killed the dog? What was the reason behind taking such an extreme step?

Dear Student,
The wicked neighbors of the old farmer killed the dog. The neighbors wanted to use the dog to get the treasure in the garden. But when they dragged the dog to the garden and made it dig the ground, they only found a dead kitten but nothing else. They became angry and furious. They kicked the dog and beat it to death. 

Hope this clears your doubts regarding this question.
Regards