The Valley of Fear

Holmes decodes a warning from Porlock, an informant against arch-criminal Moriarty, for "Douglas" resident five years at "Birlstone". Scotland Yard's MacDonald asks them to investigate a corpse with the same look and circle-in-triangle brand on the forearm as Birlstone owner Douglas. The head was blown off by an American-style sawed-off shotgun. Apparently, an intruder dropped a card with VV341...