10 February 1917 British Director of Naval Intelligence Admiral Hall receives a copy of the Zimmermann Telegram that was stolen by a British agent from a telegraph office in Mexico City. The last piece of the puzzle, this provides the copy that Admiral Hall can give to the Americans and hide the fact that the British intercepted and decoded the original.
Because this version of the telegram (from Count von Bernstorff in Washington to German Envoy Heinrich von Eckardt in Mexico City) is encrypted using the older 13040 German diplomatic code, Hall can safely show it to the Americans without revealing the British are now partially breaking the new 0075 code.
