The investigation: why my drama on Kim Wall does not name its killer | TV and radio

Hand I knew how demanding it would be to do my drama The Investigation, I’m not sure I would. But I am proud that I did. Kim Wall was a Swedish journalist and her murder, aboard a submarine in Denmark in 2017, led to a media circus. The Danish press grabbed hold of it: there was an obsession with the obscurity of what had happened, with so many theories flying around. Much of the focus was on the author.

All of this made me turn away from history. Knowing that I was a filmmaker, the parents I would meet would say, “Wow, what a story – that would make a good movie.” I thought, “Really?” Here is a story that we have heard many times before in fiction, about a man who kills a woman. Kim Wall’s name was barely mentioned by the press compared to the name of the culprit.

It wasn’t until later, when I met Jens Møller, Copenhagen Police Chief Homicide Officer, that I got a different perspective. At first, I wanted to tell him about a Chechen-Belgian terrorist who blew himself up in Denmark. But, while having a coffee, Jens ended up telling me another story, about the “submarine affair” [Wall was originally thought to have died in an accident while interviewing the vessel’s owner, who claimed he had buried her at sea. The police didn’t believe him and, 10 days later, her torso was found washed ashore.]

Jens told me about the conduct of the investigation into Kim’s death, his friendship with Kim’s parents Ingrid and Joachim, and the extraordinary efforts of scientists, divers, and police dogs to search for his body. On my bike ride home I started to think that there was a different kind of story here, not just another story of a “fascinating” man who killed a woman. We could talk about a society and a justice system that actually works, rather than humanizing the aggressor.

I didn’t want to do a cliché story about the struggle between good and evil, and all the iterations of that. It makes sense with Mindhunter [which Lindholm worked on for Netflix] because it was about the FBI and how they did things at the time. But that didn’t make sense for that. I wanted to tell a story about Jens, Kim’s parents and the humanity of it all. A story where we didn’t even need to name the author. The story just wasn’t about him.

Jens introduced me to Ingrid and Joachim. I expected this to be one of the most difficult meetings of my life, but they made it easier for me. I listened to their story and saw the respect they had for the Danish police, the divers and everyone who had worked on the case. I started planning the story and talking to the people who were there. Their participation was key: The ship that lifts the submarine from the ocean floor in the first episode is the one that did it in real life, with the same crew. We had the real divers there too, with the lead diver yelling lines at the actor playing him. Precision was very important. If I had started pretending, using my own imagination, I would have been the same as the journalists who covered it. The best part is that Iso – Ingrid and Joachim’s dog – plays by himself. Joachim insisted.

I was also able to see the emotional toll of the Jens investigation. Every time we spoke, he sort of unmasked himself, sometimes becoming upset. He began to understand what an emotional burden it had been on him, why it was his last case with the Copenhagen police. We brought part of her personal life in a humane and understandable way, and how the tragedy of another family affected her own relationships. I realized the price these people – divers, investigators, first responders – pay to do their jobs.

I felt blessed to have had the support of Ingrid and Joachim, but I also felt a lot of responsibility – and I was in control of the material more than usual. It meant so much when they were happy with the finished series. Today, one in four Danes saw it and we were able to change people’s views on the matter. The press is now talking about Kim as a reporter. The series, along with everything her parents do, is a way to ensure that she is remembered as the talented, successful and important writer that she was.

• The investigation begins on BBC Two and iPlayer at 9 p.m. on January 22.