At a first glance, the M under which symbol the French director and Special Jury Prize 2018 winner Yolande Zauberman presents her work, brings to mind the title of Fritz Lang's masterpiece, M - Eine Stadt sucht einen Mörder; and even if we are dealing here with a documentary, the resemblance is immediately revealing. M also tells of an investigation that crosses a whole city and a whole population; M, too, follows in the footsteps of a "monster" that strikes at children. However, it does not identify itself with a person: the "monster" recounted by Zauberman is the whole climate of repression and silence surrounding the child rape in the ultra-orthodox Jewish community of Bnei Brak, Israel. Menahem Lang, one who fled at the age of twenty after a childhood of abuse and followed by Zauberman's camera, conducts the enquiry and returns to the crime scenes and with poignant innocence interrogates strangers, acquaintances, friends, relatives, bringing to light the violence with disconcerting naturalness, and investigating with them the whole relationship of a community closed with its sexuality. Zauberman supports the investigation with two powerful direction choices: while leaving Menahem at the centre of the scene (he is the one who directs the inquiry and conversations), she does not exclude herself from the film, but instead takes on the role of narrator. To reveal it, her comments off-screen and above all a camera that, swinging on her shoulder, embodies her eye as a witness, thus presenting a strongly religious male world with the distance given by the gaze of a secular woman. She also chooses to film only at night, drowning her shots in a perpetual black which is not only that of darkness.