Born in Germany to Jewish Russian parents, Ze’ev Avni was taken to Switzerland as a child to escape the Nazis, and during World War II he served in the Swiss Army. A friend of his parents recruited him as a courier for a Soviet espionage network, and although he was keen to continue after the war, he was not encouraged. In 1948, fluent in Russian and German, Avni traveled to Israel to join the new Foreign Ministry in Tel Aviv, which posted him to the embassy in Brussels to negotiate trade agreements. There he was invited by the Mossad to act as a cooptee, and having been recruited he made renewed contact with the Soviets and supplied them with information from inside the Mossad.
Avni has not been allowed to disclose the extent of his work for the Mossad, but he has acknowledged participation in a false-flag operation conducted in West Germany, in which he posed as a Bundesnachrichtendienst officer to recruit sources inside Egypt’s ballistic missile development program. However, his activities were curtailed in April 1956 when, while on a visit to Tel Aviv, he was confronted by Isser Harel and charged with having supplied the KGB with Mossad secrets. He was convicted at a secret trial and sentenced to 14 years’ imprisonment, but was released after seven, in April 1963. He later served in the Israel Defense Forces as a medical aide and published his memoirs in 1999.