The Invisible Dr. Mabuse

The Invisible Dr. Mabuse is a 1962 german crime-horror film directed by Harald Reini and starring by Lex Barker; Karin Dor and Wolfgan Preiss

Plot
Strange things happen in a revue theatre. The dancer Maria seems to be hunted by an invisible admirer. When the body of a probable FBI agent is found in a trunk the police asks FBI man Joe Como for help. Como gets interested in the revue theatre and an ominous transport firm soon. When he is receiving mysterious threatening letters he is sure that Dr. Mabuse has risen again. But what is going on at "Enterprise X" so that both the goverment and the mad genius in crime are interested in it?