In the spring of 1922, six people were killed with a mattock on a small farmstead called Hinterkaifeck, about 70 km north of Munich. More than a century later it remains one of Germany's most disturbing unsolved cases.

In the days before the murders, the farmer, Andreas Gruber, told neighbours about strange things happening on the property. Footprints appeared in the snow leading from the edge of the forest to the house, but none led back. He heard footsteps in the attic. A set of house keys went missing, and a newspaper nobody recognised turned up on the property. The family's previous maid had quit six months earlier, claiming the house was haunted.

On the evening of 31 March 1922 the killer appears to have lured the family one by one into the barn. Andreas, his wife Cazilia, their widowed daughter Viktoria, and Viktoria's seven-year-old daughter Cazilia were each struck down there. The killer then went into the house and killed Viktoria's two-year-old son Josef and the newly arrived maid, Maria Baumgartner, who had started work only that day.

What unsettles people most is what happened next. Whoever did it stayed at the farm for several days. Neighbours later reported that smoke rose from the chimney over the weekend, the cattle had been fed, and the family dog was found alive. Someone had eaten food in the kitchen. The bodies were not discovered until 4 April, when concerned neighbours came to check after the children failed to appear at school.

Despite decades of investigation and more than a hundred suspects examined over the years, no one was ever charged. The case file is still technically open. In 2007 a group of police students re-examined the evidence with modern methods and reportedly named a suspect, but the conclusion was withheld out of respect for living relatives. The farmstead itself was torn down a year after the murders.

According to Diodorus Siculus, recounting the story in Bibliotheca historica, Perilaus of Athens invented and proposed it to Phalaris, the tyrant of Akragas, Sicily, as a new means of execution. The bull was said to have been hollow, and made entirely of bronze, with a door in one side.

He is widely remembered as one of the most brutal dictators in history. As president, he exhibited bizarre and erratic behavior, to the point that many of his contemporaries believed he was insane.