The Case of the Ambiguous Cipher
A. Ross Eckler · Digital Commons @ Butler University (Butler University) · 1970
... As I trudged up the hall steps of 221 B Baker Street, my attention was drawn to the door of our flat. Someone had written the letters QZHDF LPCIE OAKXC MRVMT in chalk across the upper panels. I had not the least idea what this mysterious message meant, but concluded that it might be some sort of cipher.