Hinterkaifeck was a small, isolated farm near Schrobenhausen in Upper Bavaria, about 70 kilometres north of Munich. In 1922 it was home to Andreas Gruber, 63, his wife Cäzilia, 72, their widowed daughter Viktoria Gabriel, 35, and Viktoria’s two children, Cäzilia, 7, and Josef, 2. What happened there over the last days of March that year is the most notorious unsolved crime in German history.
What happened
The family had been uneasy for some time. A maid had quit the previous autumn, saying the house was haunted by footsteps overhead. In March Andreas Gruber found a Munich newspaper on the property that nobody in the household had bought. After fresh snow fell, he found a line of footprints leading from the edge of the forest to the farm’s machine shed, whose lock had been forced, and on to the house. There were no prints leading away. At night the family heard someone walking in the attic; a search found nothing. On 31 March Gruber mentioned all this to acquaintances in Schrobenhausen. They told him to go to the police. He said he could look after himself.
That afternoon a new maid, Maria Baumgartner, 44, arrived to start work. That evening, between about seven and ten o’clock, someone drew the four adults and the elder child, one after another, into the barn and killed them with a mattock, a heavy hoe-like tool from the farm’s own stock. The killer then went into the house and killed the maid in her room and the toddler in his cot.
Whoever did it stayed. Over the following days the cattle were fed, food was eaten, and smoke was seen rising from the chimney. Travelling coffee sellers knocked on 1 April and got no answer. On 4 April a mechanic came to repair an engine, worked for an hour, and saw no one. That evening the neighbour Lorenz Schlittenbauer, with Michael Pöll and Jakob Sigl, searched the farm and found the bodies in the barn under straw and boards. The seven-year-old had survived for hours and had torn out tufts of her own hair as she lay dying.
The investigation
Detectives from the Munich police under Inspector Georg Reingruber arrived the next day. By then the scene was ruined. Neighbours and sightseers had walked through the barn, moved the bodies and even cooked in the kitchen. Autopsies were carried out on site and the skulls were removed and sent to Munich for study. A large sum of money was found untouched in the house, which undermined the first theory of robbery. The murder weapon was only found in 1923, hidden in a false floor, when the farm was demolished.
According to the Bavarian State Archives, which hold the Munich police files today, officers pursued more than a hundred lines of inquiry up to 1930 and all of them failed. Fingerprints were never taken. The family’s finances were barely examined. The mechanic who had worked at the farm on 4 April was not formally questioned until years later. A reward of 100,000 marks brought nothing useful. The files were formally closed in 1955, though the last interviews with witnesses took place as late as 1986.
The suspects
The investigation exposed the family’s tangled relationships. Viktoria and her father were widely said to have had an incestuous relationship, and the paternity of her son Josef was disputed between Gruber and Schlittenbauer, the neighbour who had been her lover. Schlittenbauer was present at the discovery, entered the house alone, seemed to know where the bodies lay, and in later years made remarks that some interpreted as inside knowledge. He sued people who called him the murderer, and won. Other theories point to Viktoria’s husband Karl Gabriel, reported killed in France in 1914 but whose body was never found; to an escaped psychiatric patient; to a pair of brothers with a violent record; and to itinerant criminals passing through. In 1951 a deathbed accusation led to one man being investigated and released.
In 2007 a group of fifteen trainee detectives at the police college in Fürstenfeldbruck took the case as a study project, going back through the surviving files with modern methods and with the help of a Munich homicide detective. They praised the thoroughness of the 1922 interviews but were sharply critical of the forensic work. They concluded they could identify the most probable killer, and chose not to publish the name out of consideration for living relatives. Their report is available through the Hinterkaifeck wiki, a volunteer archive that has transcribed much of the police material.
Where it stands
The farm was torn down within a year of the murders. A small wayside shrine marks the site, and a memorial stone to the victims stands in the cemetery at Waidhofen. The case has inspired novels, films and a stream of amateur investigation, and in 2026 the Bavarian State Archives mounted an exhibition drawn from the original police files. The crime itself is beyond doubt. The warning signs, the footprints and the intruder in the attic are in the record. What is missing, a century on, is a name.