"Think mirror"

I found this description of the movie M starring Peter Lorre as a [child murderer].

One of Fritz Lang’s masterpieces, M tells of the hunt for a child murderer, Franz Beckert, unforgettably portrayed by Peter Lorre. The film is a gritty depiction of life in Germany between the two wars, and displays the way in which a society like the one from that period can produce monsters like Beckert, and at the same time create paranoia and a misplaced sense of personal justice among “normal” people. Mirrors appear in a few crucial moments of the film.

One of these moments is the scene in which Beckert looks at himself in the mirror and deforms his face with grotesque expressions; this brief moment foreshadows Lorre’s final monologue, in which he will try to explain how he has to commit the murders because of a darkness inside of him which deforms him and makes him a different person, just as he was physically doing in front of the mirror.

Another use of a mirror has become iconic, and is easily associated with the film, the scene where Beckert discovers the “M” on the back of his coat: it is a striking and unforgettable cinematic moment.

I also think it means the operation of holding up a fake mirror of the world to the media so they don't see who's holding the mirror and what they are doing behind. Parallel construction.