In a Copenhagen court hearing, Peter Madsen—the owner and skipper of the crowdfunded, amateur-built diesel-electric submarine UC3 Nautilus—testified that the death of Swedish reporter Kim Wall aboard the Nautilus was an accident. He also claimed that threw her body into the ocean, of which only the apparently deliberately dismembered torso was recovered, because he knew his career was over and burial at sea is a maritime tradition. He also claimed it was his intention to commit suicide by taking the sub to the depths of the Baltic Sea and sinking it.

According to a report from The New York Times, the judge called his account "not reasonable" and allowed prosecutors to raise the charges Madsen faces from involuntary manslaughter to the legal equivalent of murder. Madsen remains imprisoned for at least another four weeks, until his next court hearing in October.

Wall initially approached Madsen about his efforts to build a suborbital rocket through his organization RML Space Lab (the RM standing for "Rocket Madsen," his nickname) and to launch himself into space. But she then became interested in his submarine, Madsen told the court. The Nautilus was to be used to assist in getting RML's rocket out to its launch site in the Baltic Sea.

Madsen's account was that, after a successful dive and resurfacing, he climbed up to the Nautilus' deck, opening the hatch to go topside so he could pilot the sub on the surface. But the deck and hatch were slippery, Madsen claimed, and the 150-pound metal hatch slipped from his fingers, hitting Wall in the head and knocking her back down to the submarine's interior. Madsen claimed that he then went below and checked her pulse and found there was none. He believed the hatch had fractured her skull.

Most hatches like the one Madsen claims killed Wall have safety latches specifically to prevent this sort of accident. A photo of the UC3 Nautilus with its deck hatch open, however, shows no such latches—but when fully opened, the hatch would have been held in place by gravity and would have to have been lifted to be closed.

Madsen then claimed to have gone into a "suicidal psychosis." When asked by his lawyer in court why he had not radioed for help, he said, "I realized there was nothing left of the world I was living in... I had no more plans in this world other than to sink the Nautilus."

"Sinking the Nautilus is not a suitable ending for Kim," Madsen said, "so I removed the body and did a funeral at sea, like it's been done at sea for hundreds of years." After hauling her body up with ropes and attaching an iron pipe to weigh the body down, he threw Wall's remains overboard and then steered the submarine south with the intent to scuttle it in deeper waters. He did not explain why he changed his mind and returned to port before scuttling the sub in shallow water and abandoning Nautilus as it sank.

Madsen denied having had intercourse with Wall or binding her, though he admitted to having sex with another woman on a previous voyage who held her breath to simulate choking. Madsen could not explain what happened to Wall's underwear, though he said he removed her shoes and pantyhose before trying to move her body. And when asked why he initially lied to police, Madsen said, "I wanted to see my wife and the three cats. I wanted to see them before all this was going to happen. I had no doubt that everything would come to light. I just wanted five minutes to say goodbye to my wife."