A Danish prosecutor says inventor Peter Madsen has been charged with murdering Swedish journalist Kim Wall during a trip on his private submarine, saying he either cut her throat or strangled her.

Prosecutor Jakob Buch-Jepsen said Tuesday the case is "very unusual and extremely gross."

Madsen is charged with murder as well as indecent handling of a corpse for disposing of Wall's body.

Madsen claims Wall died accidentally inside the submarine while he was on deck during the excursion in August. However, he has admitted throwing her body parts into the sea.

The start of the trial has been set for March 8. A verdict is expected April 25.