On the evening of March 31, 1922, six inhabitants of a small Bavarian farmstead located around 43 miles (70km) north of Munich, Germany, were brutally murdered by person(s) unknown. The farm at Hinterkaifeck was part of the village of Gröbern, as house number 27 ½, of the municipality of Wangen. In modern-day, it’s in Waidhofen, Bavaria, Germany, between Ingolstadt and Schrobenhausen.

The six victims were Andreas Gruber (63), his wife Cäzilia Gruber (72), their widowed daughter Viktoria Gabriel (35), Viktoria's children, Cäzilia (7) and Josef (2), and the recently appointed maid, Maria Baumgartner (44).

They were all believed to have been killed with a mattock, also known as a "grub axe". It is a hand tool used for digging, prying, and chopping. Similar to the pickaxe, it has a long handle and a stout head, combining a vertical axe blade with a horizontal cutting tool (adze) or a pick and an adze.

The Gruber family: Cäzilia Gruber, 72, stands second from left. Next to her is likely the family’s first maid, Kreszenz Rieger. To her right, Cäzilia’s daughter, Viktoria Gabriel, 35, holds Baby Josef. The young man at far left is unidentified

Before the murders, the family reported many strange events. Andreas Gruber reported hearing sounds from the attic, almost like someone was secretly hiding in the property, but nothing could be found on searching for the source of the sounds. Also, unfamiliar footprints circled the farm buildings, and a house key disappeared.

There were many blunders by the Munich police, and as days turned to months turned to years without any firm leads, speculation in the local community reached a frenzy. From Viktoria’s long-dead former husband back from the war and filled with hateful vengeance to locals with a grudge against the family.

The murders are considered one of the most gruesome and puzzling unsolved crimes in German history. The case remains unsolved to this day, over 100 years since it occurred.

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Hinterkaifeck murders case pictures