A remarkable German novel based on the author’s disturbing real-life experience of being stalked by a neighbour is to be published in the UK later this month.

Fear, a bestseller in Germany that was recently turned into a TV movie, is the work of Dirk Kurbjuweit, deputy editor-in-chief of the current affairs magazine Der Spiegel. In 2003, Kurbjuweit’s downstairs neighbour waged an eight-month campaign against the family, This included waiting in the hallway to shout at Kurbjuweit’s wife, Bettina, trying to get into the family flat through the garden, papering the walls in the hallway with notices accusing the couple of sexually abusing their children, and writing poems and letters addressed to them filled with fantasies of murder.

The day my lawyer advised me to get a gun was the day reality came to an end | Dirk Kurbjuweit Read more

Fear takes the family’s experience and gives it a crucial fictional twist – from the opening pages, the reader discovers the protagonist’s elderly father has killed the stalker. The question becomes one of complicity and whether it is ever justified to step outside the law.

“It’s an interesting question because I don’t believe that Randolph [the book’s protagonist] makes the right decision when he asks his father to help,” says Kurbjuweit, adding that the grandfather in the book, an expert marksman who collects guns, is modelled on his own taciturn parent. “The idea came about because in one of my ex-wife’s darkest moments, when this man had been lying in wait for her and shouting at her whenever she came home, she said, ‘What about your father? Couldn’t he help?’ And I thought for a minute, maybe he could, but then I dismissed it. I knew she didn’t really mean it, she was simply feeling desperate, but then a decade later I found myself thinking: what if?”

Kurbjuweit’s wife wasn’t the only person to suggest violence as a method for removing the stalker. His lawyer said that perhaps he would be better off simply getting a gun, “which was when I knew we’d entered the realm of the unimaginable because she was basically saying the law couldn’t work for us – nothing could be done”. Close friends would talk casually about how they “knew a bouncer who could take care of him”. Even the police admitted there was nothing they could do. “We thought it would be easy to get him out because he was the aggressor, but that was not the case,” says Kurbjuweit. “Because he hadn’t been violent there was nothing the state could do. We couldn’t go on living this way but we also felt quite strongly that we shouldn’t be the ones to move because we hadn’t done anything wrong.”

I don't like guns, I don't like violence – even in my darkest moments I believed that the state would help us in the end Dirk Kurbjuweit

He chose to write a novel rather than a memoir because “a memoir would have been an act of revenge and not a good book”. Instead, the central relationship is not between protagonist and stalker but rather father and son. “The character of the father is very close to that of my father,” the author admits. What did his father make of it? “He’s a man of few words. He read the book and watched the movie but I don’t know what he thought about it. I probably never will.”

Fear’s German title is Angst, and in some ways that feels closer to the uneasy currents running through the novel: this is not so much a crime story as a tale of existential crisis, of action versus inaction. Unsurprisingly, there have been arguments at public readings over whether the book’s solution is right.

“One of the things I was most interested in was how thin the line is between being civilised and acting on the side of the law and being uncivilised and ignoring the law,” Kurbjuweit says. “It’s a subject people have very strong views about. Many feel that if you are under threat then it is justified to take the law into your own hands, and sometimes I think when they realise that is not what I think it becomes disappointing for them. Myself, I don’t like guns, I don’t like violence – even in my darkest moments I believed that the state would help us in the end.”

In real life the Kurbjuweits decided on a less deadly course of action. “If the situation had continued then my wife and I had given ourselves a deadline to move to a new place to live,” he says. “It helped that we were always together on this. The experience was horrible but it also bonded us together and although we did divorce some time later that had nothing to do with this.”

In the end, his faith in the law was justified. After talking to a psychiatrist about his neighbour’s mental health issues – issues that his neighbour was aware of, Kurbjuweit adds – she agreed to assess him. “A few days later he packed a suitcase and left,” Kurbjuweit says. “He went to live in a place with other men who had difficulty integrating in society.” He died soon afterwards of a heart attack.

Does Kurbjuweit feel any sympathy for his stalker? “Not exactly, because what he did was terrible … but he had an awful life,” he says. “He was an orphan who had grown up in care homes. I later found out some terrible things had happened to him. He was a very sad person but what he did was still very wrong.”

Fear by Dirk Kurbjuweit is published by Orion on 25 January (£12.99)