Jacob grabs her mobile and calls Kai Höß in Stuttgart, who has to stay in quarantine at the moment because of a suspected Corona case nearby. His face appears on the screen. Kai Höß is 59 years old, four years older than Rainer. They grew up together in Swabia, two brothers with no other siblings.

Today Kai Höß works as a pastor in a free international church congregation where English is spoken. He lived abroad for many years.

Is it true, Herr Höß, that your brother Rainer was often beaten by your father, as were you? "No," answers Kai Höß, "my father was a gentle man. That he was a Nazi and that things were very strict at home, none of that is true. Nor did he deny the Holocaust."

Did the dictatorship begin at home over breakfast? "Of course not. That was always a really cool time. We just talked. It was a highpoint [of the day]," explains kai Höß.

Were you not allowed to play with the neighbouring Jewish kids? "Rubbish. They were nice neighbours whom we liked," he says.

Your father is said to have told a teacher that his father forgot to kill her in Auschwitz. "That’s nonsense," the pastor says. Sometimes Kai Höß laughs out loud, so unbelievable does he find his brother’s stories.

Did your brother have nine heart attacks? "Come off it. He also lied to our mother that he had an incurable disease, cancer or something. Mum often believed that," he says.

Over the years, she had given her son Rainer several hundred thousand Euros. Yet terrible conflicts did break out between the parents in those days, says Kai Höß. The mother had no self-control and died a few years ago; she had been committed to a psychiatric ward. She had also tried once to kill her husband. But with the Auschwitz commandant’s letter opener? That seems implausible.

Did the crisis in the family have anything to do with Auschwitz? "Nah, not at all." Then he says: "Rainer would like to be a victim. But a victim he is not."

Many years ago, Kai Höß explains, he used to regularly drive his brother to the police station in Calw. An arrest warrant had been issued in some fraud case. Kai Höß had begged the judge for mercy. The brother was thus spared a prison sentence, but still had to present himself to the police again and again. Yet the fraud never stopped. Kai Höß had often wondered how he could manage to reach his brother, who was now evading him and finally didn’t want to see him anymore. "In the parish we pray for Rainer," says Kai Höß, "I love him as my brother."

When the trial against his brother began in Leonberg, Kai Höß also attended court together with his wife. They had arranged to meet the author Jacob who had brought along one of her friends. They were joined by the journalist Beck, who had long been warning against Höß, as well as the plumber Diebold and the deceived pensioner. On the one side there was the phalanx of those who had been deceived – and who had in the meantime become friends and called themselves "a group" – and on the other, the man with the dirtiest of all grandson tricks. After the verdict was announced, Rainer Höß marched out of the court with a frozen expression. "Damn, kid, what’s the matter?", his older brother asked him. But Rainer Höß walked past him without saying a word.

I travel to Munich’s Institute of Contemporary History to examine the estate of concentration camp commandant Rudolf Höß. After the grandson failed to sell the estate for a lot of money, he donated the entire lot, a good 300 objects, to research. Lying there are two old letter openers. One of them, allegedly forged from shell splinters, was also allegedly the weapon used by Höß’s violent-tempered mother. Next to that is the commandant’s heat-resistant chest, allegedly a gift from Heinrich Himmler. In a box there is a small nameplate bearing the name "Höss," allegedly from the commandant’s front door. One could write an entire encyclopaedia of "allegedness" here, in which fiction and truth blur so seamlessly that only one thing is clearly recognizable: Rainer Höß, the illusionist, who juggles somewhat clumsily with set pieces of reality.

His grandfather had also beautifully embroidered his own life. This was discovered by Ulrich Nieß, the leader of the Mannheim City Archive. Writing autobiographical notes in prison, former commandant Höß described a carefree childhood and growing up in prosperity. Thus, on his seventh birthday, he was given a pony named Hans as a present. The boy loved Hans so much that he sometimes took the horse to his room. In reality, the family lived in modest circumstances in an apartment on the third floor.

Recently, in mid-March, I visited a man who grew up in Auschwitz – in a sizeable house with a brick paddling pool in the garden, a large terrace, and a dog. The concentration camp abutted the wall by their greenhouse. Back then, in the early 1940s, he was still a little boy; today he is 83 years old and lives in an apartment on the Baltic Sea. His name is Hans-Jürgen Höß and he is the youngest son of the notorious commandant. He is also the father of Rainer Höß.

Hans-Jürgen Höß sits down on his green leather sofa. On the table there is a bowl of pears and a book of crossword puzzles. On the wall next to the sofa hangs the only photo that reminds him of his childhood: of himself and his siblings. They are laughing. In the book by his son Rainer, it says that Hans-Jürgen Höß was born by caesarean section because he had to have been born on the same day as a crucial speech by Adolf Hitler.

"Oh, nonsense," says Hans-Jürgen Höß. 1937? By caesarean section? "My mother told me all about that." His mother told him that he had been born at home with no doctor present.

He has not spoken to his son Rainer since 1987, he says. A few years earlier, the father had moved out of home when the marriage came to an end. The father, who used to be a sales manager at Volvo, says of Rainer Höß: "A difficult case. I must be ashamed of myself for having such a son. I haven’t had any influence over him for a long time." Rainer had squandered his mother’s fortune, and she ended up as a welfare case in a home. "He blew it all. Awful." The television is playing upbeat pop music, Ghostbusters.

Did he hit his son and forbid him from playing with the Jewish neighbours? Did his wife fire a pistol at him? Hans-Jürgen Höß chuckles. Rainer’s stories shouldn’t be believed. "I didn’t beat the boys." Everything Rainer did was "crap." All Rainer ever did was try to turn the family name into money. "He never really worked. He just bullshitted his way through life getting up to all kinds of crooked stuff."

Was he looking for recognition? "For sure, definitely," says his father. Was he also looking for love? "He never missed out on that." He thinks for a while without saying anything. Then he finally says: "I have no idea what drives him."

So who is he then, this Rainer Höß? I believe that he was badly damaged by his family history. But that he suffered from his grandfather? Rudolf Höß was merely the surface onto which Rainer Höß projected his macabre attempt to construct an identity for himself at the expense of the Holocaust – a terribly successful business idea. The grandfather conferred meaning upon him; without this Rainer Höß would have remained a lost man. Perhaps Rainer Höß would be well advised to discuss all this with his friends, Stefan Himmler and Martin Kaltenbrunner. I have tried in vain to locate both of them. It is very possible that neither of them exist at all.

Translated by Paul Hockenos