A Danish inventor tied up and tortured Swedish reporter Kim Wall before killing her on his private submarine, according to prosecutors.
Peter Madsen allegedly planned the murder by bringing a saw, screwdrivers and pipes that were used to hit, cut and stab Ms Wall while she was alive.
According to an indictment published on Tuesday, the 30-year-old’s cause of death is yet to be confirmed – but it is believed she was strangled, or her throat was cut.
The freelance journalist was on Madsen’s home-built submarine off the coast of Copenhagen in August 2017 to interview him for an article.
She was reported missing after failing to return home from the trip on the 18m (60ft) Nautilus submarine, which then sank.
Madsen, who was rescued from the sinking vessel, has admitted dismembering Ms Wall on board and dumping her body parts in the sea, but he denies murdering or sexually assaulting her.
He has also been charged with indecent handling of a corpse, dismemberment, and having sexual relations with Ms Wall of a “particularly dangerous nature”.
In October, officers searching his laboratory found a hard drive containing images of what appeared to be women being strangled and decapitated.
Later that month, police confirmed that investigators had found 14 interior and exterior stab wounds to the journalist’s genitals.
Kim Wall had written for publications such as The New York Times, Harper’s Magazine and The Guardian – reporting from countries including Haiti, Cuba and China.
Prosecutors are likely to seek a life sentence for Madsen, which typically involves 15 years in jail without parole.
A request has been made for Madsen to be held in custody until his trial begins on 8 March.