The most vivid memory Ed Gein recalled from his childhood was the day when, burning with curiosity, he defied his parents’ strict prohibition and crept into the windowless outbuilding behind their butcher’s and grocery shop. He was able to watch unobserved as, his father holding the carcass steady, his mother – clad in a long leather apron spattered in blood – cut open a pig hanging from the ceiling so that its entrails slid out into a bucket.

Four decades later, sheriffs in Plainfield, Wisconsin, found just such a scene when, one November night in 1957, they came to search the remote and squalid farmhouse where 51-year-old Gein had lived alone since his beloved mother had died. Only this time the body hanging decapitated and disembowelled like a deer from the shed ceiling was of a missing local woman.

Bernice Worden, 58, who owned a hardware shop, wasn’t that much younger than his mother when she’d died, thereby sealing her fate at the hands of a man who provides one of the darkest entries in the annals of violent crime.

Gein, who was considered simple-minded but harmless by neighbours, was only ever confirmed to have killed two people – not even technically qualifying him as a serial killer although he was suspected of seven other murders.