Danish police add abuse of corpse charge in grisly submarine case

Danish police are putting an additional charge of abuse of a corpse to the court investigating whether Danish inventor Peter Madsen killed Swedish reporter Kim Wall on board his submarine.

Police formally identified her headless torso on Wednesday, that the body had been weighted down with metal and an attempt had been made to remove gas and air from inside it to keep it on the seabed.

Self-built submarine inventor Madsen, 46, has been held in formal custody since August 12 on suspicion of "negligent manslaughter", in a case that has shocked and intrigued people around the world.

Madsen was last seen with Swedish journalist Kim Wall before her headless torso was found floating off Denmark, with investigators claiming the body was "deliberately" mutilated and weighted down with a metal object.

Police spokesman Jakob Buch-Jepsen said the prosecutor was also adding a charge of abuse of a corpse and is expected to seek a murder charge against Madsen.

Madsen, who has denied the allegations against him, has insisted Wall died in an accident on board and that he dumped the body in the water at an undefined location in Koge Bay, south of Copenhagen.

Prosecutors have until September 5 to request an extension of his custody. 

Wall, a freelance journalist who has reported for The New York Times and The Guardian, was last seen onboard Madsen's submarine on August to interview him for a feature story.

Her boyfriend reported her missing a day later. The same day, Madsen was rescued from waters between Denmark and Sweden shortly before his submarine sank.

Investigators recovered and searched the sunken submarine, which police believe Madsen sank intentionally.

The cause of death and motive remain unknown.

Manslaughter carries a sentence of between five years and life in prison.