On the night of March 31, 1922, the six residents of Hinterkaifeck, a small farmstead in Germany, were murdered with a mattock (a tool similar to a pickaxe). The victims were Andreas and Cäzilia Gruber, their widowed daughter Viktoria, her children Cäzilia and Joseph, the maid, Maria Baumgartner. It was rumored that Andreas and Viktoria had an incestuous relationship, and that Joseph was their son. The Gruber's earlier maid left the family six months earlier, having claimed the home was haunted. And days before the murder, Andreas told neighbors he'd discovered a strange set of footprints in the snow leading from the forest to the home, but not back. He'd also heard footsteps in the attic, and a set of keys went missing. Based on the crime scene found days after the murders, investigators believed the family was led one by one into the barn to be killed, before the murderer killed the maid and young Joseph in the house. More than 100 suspects were ultimately questioned, but none were ever convicted of the crimes.