The typical Krimi movie of the Sixties contains a number of distinct stylistic traits, which not only made the films a true series, but - seen in context with other, similar German crime movies of that time - makes it a true film subgenre as well.
In 1959, the Danish company Rialto Film, with its producer Preben Philipsen produced Der Frosch mit der Maske (based on The Fellowship Of The Frog), targeting the German film market. The film turned out to be surprisingly successful and started a veritable fad of crime movies, known as Krimis (abbreviation for the German term "Kriminalfilm" (or "Kriminalroman")) which would last until significant changes in the direction of the German film industry in the early Seventies occurred. Rialto Film soon acquired the exclusive rights to nearly all the Edgar Wallace novels, founded a German subsidiary company and, unconcerned by the many copycat productions by others, moved towards the artistic and commercial peak of the series in the first half of the Sixties.