Late in life Arthur Conan Doyle pursued an interest in the possibility of spiritualism and existence beyond the grave. He was widely criticized for this, but a writer to the Graphic raised a redeeming point:

Although we may misbelieve mediums and
With doubt and suspicion our minds may be filled,
Sherlock Holmes, we must grant, reappeared in the Strand
A number of times after having been killed.

Indeed, Holmes had returned against his creator’s wishes. “I never thought they would take it so much to heart,” Conan Doyle once wrote of Holmes’ death. “I got letters from all over the world reproaching me on the subject. One, I remember, from a lady whom I did not know, began ‘You beast’.”

Life After Death | Futility Closet.