Operation Neptune (espionage)

Operation Neptune was a 1964 disinformation operation by the Czechoslovak secret service, the StB, involving Nazi-era documents.
In 1964, the StB publicly claimed to have discovered Nazi-era intelligence files hidden beneath the surface of Černé jezero, a lake in the Šumava, on the border with West Germany. The four chests containing the papers were supposedly discovered during the making of a documentary, in the presence of members of the Western press. In fact the agency itself had placed them there, in collaboration with the KGB.
The papers were possibly genuine, although former Czechoslovak spy Josef Frolík described them in his 1975 memoirs as forgeries. However, their apparent discovery was a disinformation operation, the largest conducted by the agency; in fact the papers found in the sunken chests, which had been carefully doctored to appear as if they had been submerged since World War II, were not the real documents, which were only later brought from the Soviet Union. The agent who led the divers to make the discovery and who had originally placed them in the lake, Ladislav Bittman, (later known as Lawrence Martin-Bittman) defected to the West in 1968 and published a book on the plot. The objectives were to discredit Western politicians by revealing the names of former Nazi informants whom they were still using as spies in Eastern Europe, and to place pressure on West Germany to extend the statute of limitations on prosecution of war criminals. The operation had some temporary success, including extension of the statute of limitations.
The Czech civilian defence agency posted the files on Operation Neptune to its website.