On a remote German farmstead in 1922, an unknown assailant used a mattock to systematically murder all six residents of the Hinterkaifeck homestead, luring most of them into a barn one by one. The crime was preceded by bizarre events, including the discovery of footprints in the snow that led to the property but not away, and unexplained noises coming from the attic. Chillingly, evidence suggests the killer remained on the farm for several days after the slayings, feeding the cattle and eating food from the kitchen before vanishing. Despite an extensive investigation that ruled out robbery as a motive, the perpetrator of this meticulously executed massacre was never identified.