In March 1922, six people were killed on the isolated Bavarian farmstead of Hinterkaifeck: Andreas and Cäzilia Gruber, their daughter Viktoria Gabriel, Viktoria's two young children, and the newly arrived maid Maria Baumgartner. The farm showed signs of unease before the murders - reported footprints in the snow, a missing key, and noises in the attic - and after the killings, the animals were still cared for long enough to delay discovery. More than a century later, the farm is gone, much of the record is damaged or lost, and the killer has never been legally identified.