A mystery film is a genre of film revolving around the solution to a problem or a crime. It focuses on the efforts of a protagonist to solve the mystery by means of clues, investigation, and deduction.
^Crowther, Bolsey. [THE SCREEN IN REVIEW; 'The Third Man,' Carol Reed's Mystery-Thriller-Romance, Opens Run of Victoria."] New York Times. 3 February 1950. 1 February 2021.