Danish police say that inventor Peter Madsen has admitted to dismembering Swedish journalist Kim Wall, who was researching a story in August on board a submarine he built. He denies killing her and maintains that her death was an accident, authorities say.

Madsen was alone when he was rescued from the sinking UC3 Nautilus, which police believe he sunk deliberately. As NPR's Colin Dwyer has reported, he initially claimed that he dropped Wall off safely the same day they set out — then he changed his story, saying he "buried her at sea" after a heavy hatch fell on her head.

Divers later found Wall's severed head in Denmark's Køge Bay. As NPR's Amy Held reported, police said there were "no signs of fracture or blunt force trauma to the skull," casting doubt on Madsen's claims. The head was in a bag weighted down with metal, authorities said.

Now, according to a Copenhagen police statement, Madsen has changed his story once again. He says that Wall died from carbon monoxide poisoning inside the submarine while he was sitting on the submarine's deck.

During an interrogation on Oct. 14, police say, Madsen said that after Wall died, he dismembered her body and threw the remains in the bay.

"This explanation (by Madsen) naturally will lead the police into gathering additional statements from the coroner and the armed forces' submarine experts," Copenhagen police investigator Jens Møller Jensen said, according to an Associated Press translation.

As The Two-Way has reported, "Madsen has been charged with manslaughter, the legal equivalent of murder in Denmark." Police say they have added an additional charge — sexual assault without intercourse — in light of some 14 stab wounds in and around Wall's genitals. Madsen denies the accusations.

A headless female torso washed ashore on Aug. 21, police say, and was identified as Wall two days later using DNA evidence.

At a previous hearing, prosecutors presented evidence of a hard drive with images of tortured and murdered women that they said was found in Madsen's laboratory.

Police said Monday that Madsen has voluntarily agreed to remain in custody through Nov. 15, which means there is no need to conduct a hearing tomorrow, as originally scheduled.

Wall, who was 30 when she died, wrote prolifically from all over the world in publications such as The New York Times, Harper's Magazine and The Atlantic.

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