STOCKHOLM (AFP) - The Danish inventor of a do-it-yourself submarine has said that a Swedish journalist missing since Aug 11 died in an accident on board the vessel, and that he dumped her body in the sea, Danish police said on Monday (Aug 21).

The inventor, Peter Madsen, had been claiming that he last saw Ms Kim Wall when he dropped her off on the tip of an island in Copenhagen late on Aug 10.

The Danish authorities have been searching for Ms Wall, a 30-year-old reporter who had been writing a feature story about Madsen, since she failed to return from an interview with him aboard the 18m Nautilus.

But Madsen, who has been accused of negligent manslaughter, "told police and the court that there was an accident on board the sub that led to the death of Kim Wall, and that he subsequently buried her at sea in an undefined location of the Koge Bay" south of Copenhagen, police said in a statement.

The two were sighted on board the vessel by several people in waters off Copenhagen on the evening of Aug 10.

The sub was also reported missing, but rescue crews located it around midday on Aug 11 in Koge Bay, about 50km south of the Danish capital.

Just after being found, Madsen was rescued and the submarine suddenly sank.

The Nautilus was the biggest private sub ever made when Madsen built it in 2008.