According to her family, Wall, 30, was writing a piece about Madsen, 46, an amateur rocket builder known in Denmark for using crowdfunding to build submarines and rockets. Wall — a freelance journalist who had reported from Sri Lanka, the Marshall Islands and North Korea — boarded the submarine on Aug. 10 and was reported missing on Aug. 11. That day, Madsen was pulled from Koge Bay after police say he deliberately sank his submarine.
Madsen was taken into custody on Aug. 12, and his trial is expected to begin in March.
Since August, Madsen's retelling of what led to Wall's death has changed repeatedly. He is being held in Vestre Prison in Copenhagen and has been charged with manslaughter.
In September, Madsen told a Danish court that he was showing Wall around his boat when he lost his grip on a 150-pound hatch, which then collided with Wall's skull. He said he panicked and gave Wall what prosecutors called a “burial at sea.”
“In the shock I was in, it was the right thing to do,” Madsen told the court, according to Agence France-Presse.
Reuters reported that Madsen said “there was a pool of blood where she had landed” before he panicked and tossed her lifeless body overboard.
Yet when divers discovered Wall's dismembered remains in early October, the gruesome details of that “burial” began to cast doubt on Madsen's testimony. The Associated Press reported that Wall's severed legs were found in plastic bags weighted with metal, while her recovered head showed no signs of fracture, like it would have if struck by a hatch.
Another bag contained a knife, along with Wall's clothing. A naked torso had been found in the same waters weeks earlier and had been stabbed 15 times, according to the AP.
But even Madsen's claim that he gave Wall at “burial at sea” contradicted what he told police immediately after her disappearance. Madsen initially claimed he dropped Wall off on shore in Copenhagen before his submarine — a 60-foot UC3 Nautilus — sank.
But once police pulled the boat up from the sea floor, they discovered blood inside. Madsen was arrested on a manslaughter charge and accused of scuttling his own ship. Authorities matched blood found inside the submarine with DNA from the torso and from Wall's toothbrush and hairbrush, police said in a news conference.
When the torso washed up on shore several days after the submarine was recovered, Madsen conceded that Wall had died on board. But he claimed it was an accident caused by the falling hatch. The charges against Madsen were then upgraded to murder.
“Two people are on a boat. Her legs and head and arms were cut off, and we can prove that,” Jakob Buch-Jepsen, special prosecutor with the Copenhagen police, told The Washington Post in September.
Madsen has told prosecutors that he was interested in sadomasochism and had had sex onboard the Nautilus before. In September, a Swedish newspaper quoted Madsen's defense lawyer as saying Madsen was “not quite like other people” in his sexual preferences, despite his being harmless. Madsen still denies having sex with Wall, according to Monday's news release.
Yet in early October, prosecutors said they had discovered videos on Madsen's computer of women being tortured and decapitated. Buch-Jepsen said he and his colleagues presumed the images “to be real.”
Madsen said during the pretrial session that the computer hard drive — which was found in a laboratory run by Madsen — didn't belong to him but instead were part of tools “used by everyone in the laboratory.”
Monday's news release said that over the past two weeks, several dives had been carried out to find Wall's arms and cellphone. The dives have so far been unsuccessful.