The Swiss Conspiracy (1976) on Netflix

Plot summary

Swiss bank secrecy makes numbered accounts a place to hide money, and Hurtil Bank in Zurich receives anonymous letters threatening to expose its depositors unless it pays ten million francs. Five account holders also get letters demanding one million francs each. Bank president Johann Hurtil, hoping to avoid scandal and the police, hires David Christopher, a former U.S. Justice Department official who runs a consulting firm in Geneva. The clients include Denise Abbott, a European socialite who does not have the money demanded, Chicago gangster Robert Hayes, Texas businessman Dwight McGowan, Amsterdam businessman Mr. Kosta, and Mr. Rascha, an arms dealer shot dead in a restaurant after his letter arrived. Hayes, prosecuted by Christopher in the United States, resents his presence on the case, and Captain Frey of the Swiss police takes an interest in Christopher's business.