The Hinterkaifeck farmstead was a lonesome place. Located near the woods outside the Bavarian town of Gröbern, about an hour’s drive from Munich and a half-mile behind, or “hinter,” the town of Kaifeck, it was the home of 35-year-old Viktoria Gabriel and her two children, 7-year-old Cäzilia and 2-year-old Josef, as well as her elderly parents Andreas and Cäzilia Gruber.

The family was known for keeping to themselves. Still, neighbors grew concerned on April 1, 1922, when young Cäzilia missed school and the entire family failed to show up to the church where Viktoria was a member of the choir. Cäzilia missed school again on April 3, and by then, mail for the family had begun to pile up at the local post office. On April 4, the family’s neighbors decided to investigate. Lorenz Schlittenbauer, a farmer who lived nearby, led the search party.

What they discovered likely haunted them for the rest of their days.

In the barn, the search party found four battered bodies covered with hay. Inside the house, they discovered the bodies of 2-year-old Josef and the maid, Maria Baumgartner. It had been Baumgartner’s first day on the job—the previous maid had abandoned her position due to a fervent belief that the house and farm were haunted.

For more than a century, dozens of people have been arrested as suspects in the crimes, though no one has ever been found guilty. The Hinterkaifeck murders remain one of Germany’s eeriest—and most famous—unsolved crimes.

Footsteps in the Snow

The reports from the family’s autopsies, conducted by court physician Dr. Johann Baptist Aumüller, paint a horrifying picture of their injuries. The elder Cäzilia showed signs of strangulation and seven blows to the head, which left her with a cracked skull. The face of her husband, Andreas, was caked with blood, and his cheek bones protruded from shredded flesh. Viktoria’s skull was also smashed; her head showed nine “star-shaped” wounds and the right side of her face had been hit with a blunt object. The younger Cäzilia’s lower jaw had been shattered and her face and neck covered in gaping, circular wounds.

While the elder Cäzilia, Andreas, and Viktoria likely died instantly from expertly delivered blows from a mattock—a pickax-like tool used for digging and chopping—the autopsy found that the younger Cäzilia likely remained alive and in shock for several hours after her attack. She had ripped her own hair out in clumps.

Inside the farmhouse, little Josef and the maid Maria Baumgartner had met a similar fate. Maria was killed by crosswise blows to the head in her chambers, and Josef by a heavy blow to the face in his cot in Viktoria’s room. Like the bodies in the barn, theirs were also covered: Maria’s with her sheets, and Josef’s with one of his mother’s dresses. The farm animals and a Pomeranian watchdog remained unharmed. Chillingly, they had even been taken care of and fed in the several days that passed between the murders and their terrible discovery.

Police initially suspected vagrants or other traveling men of ill repute, but tossed out this theory after large sums of money were found within the house. Besides the bodies and the hay and bedsheets used to cover them, nothing had been disturbed—though the killer clearly remained at the farm for several days, feeding the animals, eating meals, and lighting fires in the hearth. When the police questioned the former maid about her belief that the property was haunted, she said she had come to that conclusion after constantly hearing sounds in the attic and experiencing an unsettling feeling of being watched.

Though Andreas had not believed her, he too had confided in neighbors about some strange happenings in the days before the murders: A newspaper he did not buy was found in his home, and a set of footsteps was discovered leading from the forest to the farmstead. The footsteps were set in pristine and unmarked snow, leading in only one direction. Nobody at Hinterkaifeck knew whom they belonged to.

To make matters even stranger, one of the family’s two keys disappeared shortly before the murder. Combined with the footsteps from the woods, sounds in the attic, and a smoking chimney in the days following the crime, these odd details comprise a profile of a ruthless intruder who may have taken up residence in the house.

Private Mysteries

Suspicion eventually settled on several men connected to the family, in part because of some domestic turbulence at the farm.

Viktoria was a widow whose husband had died in World War I, and her son Josef’s father remains unidentified to this day. She had had a relationship with Lorenz Schlittenbauer (or Schiebebauer)—the man who had led the search party that discovered the bodies—and both had publicly referred to Josef as their child. They planned to get married—until Andreas interfered, and their relationship ended. Schlittenbauer eventually married someone else and they had a child who died in infancy.

Police zeroed in on Schlittenbauer as a suspect. They theorized that—traumatized by the death of his baby and unwilling to pay child support for Josef—he had come to the farm (located only a few hundred yards from his own) and murdered Viktoria and her family. The theory was bolstered by the fact that those with him during the initial investigation had found his behavior suspicious; they said that he acted nonchalant, viewing and handling the bodies without signs of repulsion. He also knew his way around the farm.

The police questioned Schlittenbauer extensively, but were unable to conclusively place him at the crime scene. His behavior could be explained by shock, they reasoned, and his knowledge of the farm by his relationship with Viktoria.

With Schlittenbauer eliminated, police considered Viktoria’s husband, Karl Gabriel, a suspect, theorizing that he was actually alive and had come back from the war and killed them. That theory didn’t last long: They soon discovered that he had been slain in France on December 29, 1914, in the first few months of World War I. Many of his fellow soldiers attested to seeing his body.

Another theory floated at the time was that Josef was actually the child of Viktoria and her own father, Andreas, and that one of them had killed the entire family before turning the mattock on themselves. Andreas’s proclivities for incest and abuse were frequently discussed in the neighboring town; supposedly, Andreas had had other children with Cäzilia besides Viktoria, but she was the only one to survive his violent hands into adulthood. But none of the injuries to the bodies could be explained as self-inflicted, so it wasn’t possible that the crimes were a murder-suicide perpetrated by Viktoria or Andreas.

The murderer had to be someone who didn’t live at the farm. But who?

Only one thing could be stated with any degree of certainty: The crimes had been committed by someone who knew their way around a farm, as evidenced by the continued upkeep after the murders and by the expert wielding of the mattock. The brutality of the murders suggested that they had been committed by someone with a personal vendetta against one or several of the Grubers.

But police at the time failed to come up with answers and eventually closed the case—though it would not remain closed.

Silent Skulls

The Hinterkaifeck case has been reopened several times. Even clairvoyants have been given a chance at it—in his book Hinterkaifeck: Spuren eines mysteriösen Verbrechens (“Hinterkaifeck: Traces of a Mysterious Crime”), author Peter Leuschner details how the bodies of the Gruber family and the maid were beheaded not long after the original autopsies and the skulls sent on to Munich, where they were examined for metaphysical clues. Sadly, the skulls did not speak.

In 1923, the farm was demolished, and the family lays buried—without their heads—in a plot in Waidhofen. The skulls were lost during World War II. Initial evidence gathered at the crime scene is either lost or too old and degraded to give up any secrets, though in 2007 the Fürstenfeldbruck Police Academy took the Hinterkaifeck Murders on as a cold case. Because of the relatively basic forensic techniques employed during the original investigation, as well as missing evidence and the later deaths of some suspects, they were unable to conclusively identify the murderer—though they did all agree on a theory.

Out of respect for surviving family members of people related to the crime, however, that theory remains a secret. At this point, it seems unlikely the public will ever know who committed the murders, or why. Whatever secrets the Gruber family kept in life and death, they now slumber alongside them in the grave.

A version of this story originally ran in 2017; it has been updated for 2023.

This article was originally published on www.mentalfloss.com as The Chilling Story of the Hinterkaifeck Killings, Germany’s Most Famous Unsolved Crime.