Karl Ludwig Diehl was a German film actor. He appeared in 66 films between 1924 and 1957. His father was Karl Diehl, the German professor of Anarchism.

The Copper, or The Grasper, is a 1930 British-German crime film directed by Richard Eichberg and starring Hans Albers, Charlotte Susa, and Margot Landa. It is the German-language version of the British film Night Birds, which was also directed by Eichberg but with an English-speaking cast. Both films were made by British International Pictures at their Elstree Studios at a time when such multiple-language versions were common.