Sein letzter Fall (1976)

Private detective Fritsch from Munich had received a lucrative assignment: he was to obtain proof of inheritance for a Mr. Seligmann from Canada; this would bring the client a sum of five million dollars. He is therefore looking for an old document that was hidden in a valuable painting that disappeared decades ago. The starting point is a trail that leads to a town in Poland. The painting in question is said to have disappeared there in the final years of the Second World War. But the object of desire cannot be found here, and a new clue points to a grave in Frankenthal in the German state of Rhineland-Palatinate. Fretsch then found out that the painting must probably be in the villa of a personality with significant influence in the economy and politics of West Germany. Fretsch manages to get in touch with the wife of the presumed new owner of the painting and to find out the secret of his rise to multimillionaire status. But the people concerned use their resources to counterattack.