COPENHAGEN, Denmark — The headless torso of Swedish reporter Kim Wall, whose death after taking a trip on a homemade submarine remains a mystery, was found naked and police are now searching for her clothes, Danish police said Thursday.

The 30-year-old Wall was last seen alive Aug. 10 aboard the submarine of Danish aerospace and submarine enthusiast Peter Madsen. The cause of the journalist’s death is not yet known, police said. Police have arrested Madsen on suspicion of manslaughter.

Prosecutor Jakob Buch-Jepsen said Thursday that police expect to raise the preliminary charges against Madsen to murder and indecent handling of corpse when he appears at a hearing Sept. 5 on whether his pre-trial detention should be extended.

Divers and members of the Danish Emergency Management Agency were combing the coast off Amager island in Copenhagen, where Wall is believed to have died, looking for an orange turtleneck blouse, a black-and-white skirt and white sneakers, Copenhagen police spokesman Steen Hansen.

A cyclist discovered her torso Monday. Copenhagen police say the body’s head, arms and legs had “deliberately been cut off.” DNA tests have confirmed the torso was Wall’s and dried blood found inside the submarine, which somehow sank during the trip, also matched her DNA.

According to her family, Wall was working on a story about Madsen, 46, who dreamed of launching a manned space mission.

Madsen initially told police he had let Wall off the submarine on an island. He later told police he buried Wall at sea after an accident aboard his submarine, UC3 Nautilus.

The Ekstra Bladet tabloid, quoting unnamed sources, said Madsen has asked to be transferred to solitary confinement, allegedly out of fear of being attacked inside the prison.

On Wednesday, a candlelight vigil was held at the Columbia University School of Journalism in New York, where Wall studied.

Norway-based investor Georg Poul Artmann, who holds about 75 percent of the shares in the Rocket Madsen Space Lab company that owns the 40-ton, nearly 18-meter-long (60-foot-long) submarine, told Denmark’s Berlingske newspaper he will “clean up” within the company following recent events. He did not elaborate.

Artmann said his fascination with space had prompted him to invest 250,000 kroner ($40,000) to support Madsen’s space activities. He also said Madsen was the company’s day-to-day leader and as “an investor I have not interfered in the daily operations.”

A self-taught engineer, Madsen was one of a group of entrepreneurs who founded Copenhagen Suborbitals, a private consortium to develop and construct submarines and manned spacecraft. However, the group split up in 2014 and the Rocket Madsen Space Lab was created.