Operation Neptune was a 1964 disinformation operation run by Czechoslovak intelligence (StB) with KGB support. StB officers sank chests of Nazi-era documents, some genuine and some prepared to embarrass Western targets, in the Black Lake (Cerne jezero) in the Sumava forest near the West German border, then arranged for them to be “discovered” by divers during the filming of a Czechoslovak television documentary. The find was publicized internationally as a cache of lost Nazi archives.

The aim was to influence West German debate over the statute of limitations for Nazi war crimes, then due to expire in 1965, to portray the Federal Republic as harboring former Nazis, and to discredit Western figures named in the papers. Ladislav Bittman, who helped organize the operation as deputy chief of the StB disinformation department, later described it in detail. It is a classic example of active measures that mixed real and fabricated material and exploited legitimate historical concerns.

Sources

• Bittman, Ladislav. The Deception Game: Czechoslovak Intelligence in Soviet Political Warfare. Syracuse University Research Corporation, 1972.
• Rid, Thomas. Active Measures: The Secret History of Disinformation and Political Warfare. Farrar, Straus and Giroux, 2020.

Summary entry. A fuller, document-based profile is in preparation.