the testament of dr. mabuse (), also called the last will of dr. mabuse, is a 1933 german crime-thriller film directed by fritz lang. the movie is a sequel to lang's silent film "dr. mabuse the gambler" (1922) and features many cast and crew members from lang's previous films. the film features rudolf klein-rogge as dr. mabuse who is in an insane asylum where he is found frantically writing his crime plans. when mabuse's criminal plans begin to be implemented, inspector lohmann (played by otto wernicke) tries to find the solution with clues from gangster thomas kent (gustav diessl), the institutionalized hofmeister (karl meixner) and professor baum (oscar beregi sr.) who becomes obsessed with dr. mabuse.