'Undercurrent': Why Ditte Dyreborg Is the Breakout Star of the Submarine True-Crime Doc


The two-part HBO true-crime documentary revisits the mysterious murder of a Swedish journalist.

Undercurrent: The Disappearance of Kim Wall is filmmaker Erin Lee Carr’s latest, must-see true-crime documentary. The two-part, HBO series chronicles the events leading up to the 2017 submarine murder of accomplished journalist Kim Wall, whose body was dismembered and left at sea by eccentric entrepreneur Peter Madsen. One person involved in the investigation of the case to unexpectedly emerge as the series’ most fascinating personality is Royal Denmark Navy Lt. Commander Ditte Dyreborg. 

“As soon as I knew about Ditte and started conversations with her, I said, ‘There’s even more here than people might know about the investigation,” Carr tells ET, adding, “You can’t get more of an expert on submarines than somebody like Ditte, who knows everything. And she ultimately met Peter early in his life.”

Making her first appearance in the premiere episode, “Part One: The Crime,” Dyreborg reveals that she was familiar with Madsen’s small fleet of private submarines – and seemingly very unfazed by his celebrity persona. “Immediately, when I heard the submarine was missing, I was like, ‘Oh it had finally happened,’” she recalls, noting that she felt Madsen’s design was dangerous.


It wasn’t until she heard that Wall was also on board that she suspected something bad had happened. “In my opinion, there’s something wrong here,” Dyreborg says, recalling how she told the police to arrest him. “I said, ‘No, no, no. A submarine doesn’t sink like that. You could have saved it.’ So, there’s something wrong here. And there’s still one person missing.” 

Later, when the submarine is pulled out of the water, Dyreborg is the person who goes down inside the vessel to search for Wall or any evidence of a body. “Kim Wall was not in the boat. But it was a big mess, the boat. Everything was washed around. I saw something that looked like a piece of flesh,” the commander says, before recalling how the liquid in the sub smelled distinctly like blood. 

“Many people say, ‘How do you know how blood smells?’ And I say, ‘Because I know about it.’ When it leaves the body at high pressure and it’s wet, it has a particular smell,” Dyreborg says, before revealing that two of her fingers had been cut off. “This was from an accident once.” 

“And then she told me that it was a drinking accident and then she was like, ‘It was a joke,’” Carr says, before recalling what it was like to talk to her on camera. “Ditte holds up her hand and she’s missing two fingers. And she said, ‘I know what blood smells like.’ I’m sitting there in the interview. I was slightly, like, time hungover. It was my second day in Copenhagen. And I was like, ‘Wait, what? What’s going on?’” 

While it was a shocking moment, it proves just how fascinating Dyreborg is. “Ditte definitely is a star and Ditte knows that she’s a star,” Carr says, noting that the commander was upset that she was left out of the narrative around the investigation, most notably the Danish-language scripted HBO series from Mindhunter director Tobias Lindholm, which focused mostly on the police and the prosecutor. 

“She was very frustrated that she was left out of the mainstream telling. You know, not one particular piece, but in general,” Carr continues. “So I knew it was a comprehensive, fully rounded story when I got to interview her and go around and understand what happened.” 


Dyreborg went on to testify in Madsen’s trial, where the defendant lied about what happened on the submarine and with Wall. “Peter Madsen was somebody that lied on the stand again and again and again, because it’s not illegal to lie in Denmark,” Carr says. 

One of Madsen’s claims was that Wall died after inhaling exhaust fumes. “We have not been able to detect CO2 in the submarine. And the experience from military submarines is that it wouldn’t pose a significant risk,” Dyreborg said in court at the time. According to reports, she was one of the final witnesses called in his case. 

“You know, some people think that they are smarter than everyone else,” Dyreborg says on camera. “I was called in by the police every time he changed his explanation.” 

In the end, Madsen was found guilty of murder and was charged with indecent handling of a corpse and sexual assault. He was sentenced to life in prison, where he remains today. 

Undercurrent: The Disappearance of Kim Wall is now streaming on HBO and HBO Max.