The German name applied by the Swiss Bundespolizei to a Soviet spy ring, led by a Hungarian, Rudolf Rössler, that was active in Switzerland during World War II. It acquired high-quality military intelligence about the Nazis and passed it to wireless operators for transmission to Moscow. The first two radio operators, Edouard Hamel and Margaret Bolli, were arrested in October 1943 after their traffic had been monitored for some months, and the third, an Englishman named Alan Foote, was caught while transmitting from his apartment in Lausanne at the end of November 1943. In the highly compartmented spy ring, all three had been run by a Hungarian cartographer, Sándor Radó, who escaped to Paris in 1944 and was evacuated to Moscow. Code-named DORA, an anagram of his surname, Radó had avoided direct contact with Rössler, who was code-named LUCY, and seemed to have liaised closely with a branch of Swiss military intelligence headed by Hans Hausamann that had penetrated Nazi Germany with a network known as VIKING.
The precise relationship between Hausamann and Rössler has never been clarified, but when Rössler was arrested after the war on a charge of having spied for Czechoslovakia, he was quickly released, prompting speculation that he had always acted for the Swiss.
Intriguingly, some of the messages intercepted and read by Swiss cryptanalysts suggested that Moscow Center was equally keen to learn the sources of Rössler’s information, code-named TEDDY, ANNA, OLGA, and WERTHER, but he never identified them. As all the participants are now dead, and the memoirs written by Foote, Handbook for Spies, and Radó, Codename DORA, do not identify them, only the permanently sealed Swiss intelligence archives can explain the Rote Drei’s true sources.