Madsen, 46, is charged with manslaughter, which carries a sentence of between five years and life in prison.
On Thursday the BBC and AFP reported prosecutors are expected to ask for the new charges when Madsen appears in court in early September.
Prosecutor Jakob Buch-Jepson said police are expected to raise the charges to murder and indecent handling of a corpse. “We will make an ongoing assessment of whether it should happen before,” he told the B.T. tabloid.
Police spokesman Jens Moller said the torso had suffered damage, suggesting “an attempt to make sure air and gas inside should leave the body so that it would not rise from the seabed.”
He added: “There was also some metal attached to the body, allegedly also to make sure the body would sink to the bottom.”
Madsen told a court hearing that Wall, who had not been seen since 10 August when she went to interview him on his home-made UC3 Nautilus submarine, had died in an accident and he had buried her at sea.
He had earlier claimed he had dropped her off alive in Copenhagen. His lawyer Betina Hald Engmark told Reuters he was maintaining his innocence and sticking to his account that Wall’s death was accidental.
A day after taking Wall, 30, out on his submarine, the inventor was rescued after the vessel sank. Police found nobody else on board.
Moller said there were indications Madsen deliberately sunk the submarine. The cause of the journalist’s death is not yet known, police said.