COPENHAGEN — Prosecutors in Denmark said on Thursday that they intended to ask a court to charge Peter Madsen, the Danish inventor arrested in the death of a Swedish journalist onboard his submarine, with the legal equivalent of murder.

A cyclist discovered the dismembered body of the journalist, Kim Wall, near Copenhagen harbor on Monday, 11 days after she boarded Mr. Madsen’s 55-foot submarine and went missing. An accomplished freelance reporter who was about to move to China with her boyfriend, Ms. Wall, 30, had told her family she planned to write an article about Mr. Madsen.

Mr. Madsen, 46, had been charged with involuntary manslaughter, but will now face the more serious charge of manslaughter in his next court appearance, scheduled for Sept. 5. (In Danish law, manslaughter implies intent and is the legal equivalent of murder.)

He will also face an additional charge of “indecent handling of a body.” It will up to the court to decide whether to accept the charges.