'The Tenderness of Wolves' (1973)– Ulli Lommel.

Fassbinder! Lommel! Raab! First time director Ulli Lommel's skin-crawlingly sinister 'Tenderness of the Wolves' has a truly sublime film-making pedigree! Vividly written, and aggressively performed with a feral, unnerving intensity by a catastrophically creepy Kurt Raab, whose singularly cruel, morally repugnant, utterly inhuman predator's foul, opportunistic crimes frequently prove to be wholly indigestible. Lommel's artfully fashioned psychodrama proves to be a grimly compelling dissection of the diabolically degenerated lusts of an especially profane serial killer! 

This fascinatingly macabre, mortuary cold dramatisation of the excruciatingly grisly, flesh-harvesting machinations of notorious cannibal killer Fritz Haarmann, more colloquially known as either 'The Butcher of Hanover', or the 'Vampire of Hanover' has an undeniably twisted charm, Ulli Lommel's morbidly mesmeric, disturbingly realistic true crime chiller has certainly lost none of its extraordinarily visceral power to nauseously curdle sensitive stomachs, and murderously make mystery meat out of the viewer's pulverised nerves...'The Tenderness of Wolves' is a blood-mad bear in Wolf's clothing!'