“Most of us would be capable of murder in the right situation”

Nesbo admits that the books are based on his relationship with his own brother Knut, who died of cancer in 2013 at the age of 51. “He was a year younger than me, which I guess makes me Roy and him Carl. And there are similarities, for example he is the more extroverted and I am the more introverted of the two.”

How smooth was their relationship? “There's a reason the most famous brother story is that of Cain and Abel. I loved my brother, but he could annoy me more than anyone else, especially because he repeated the same mistakes I had made, a year late.”

“But we were very close. One day when we were 11 or 12, our parents went on holiday to Europe and our mother brought us these lederhosen. We said we would wear them to school for a day. And so we sat back to back at recess” – he raises his fists in the air – “and said: 'Come on, we know, two kids in matching lederhosen that their mother made them wear, we're ready.' Those were real experiences that bonded us together.”

Like his brother, Knut also became a professional footballer. “I only played for a short time before I got injured, but my brother played in the Norwegian Premier League for several years.” Knut was also a guitarist for Di Derre. “The last recording [he did] with the band when he was quite ill, we did it in his kitchen, like an unplugged session. We filmed it and it was really touching that he was very reduced but could still play.”