In the series 4 finally of BBC's Sherlock, we learn that
Sherlock & Mycroft's sister Eurus apparently killed Sherlock's dog, RedBeard, and hid his body where no one would find it.
Later in the episode, we learn that
RedBeard was actually Sherlock's best friend, not a dog, and that he was buried in a well on the family's property.
Given that, how is it possible that
no one found RedBeard?
Wouldn't the search have been rather exhaustive, and wouldn't that have been one of the first places everyone would look?