Danish police said Sunday they had found nobody in the wreck of a submarine owned by an inventor charged with the manslaughter of a woman who had been on board — but added the vessel seems to have been deliberately sunk.

Police have said that Swedish journalist Kim Wall, 30, is missing after taking a ride on Peter Madsen's homemade 17-meter-long sub, which sank Friday morning. Madsen was later rescued by the navy.

Madsen, 46, has been ordered to be held in custody for 24 days, accused of Wall's manslaughter.

The vessel was recovered Saturday from Koge Bay, south of Copenhagen, where it had been lying at a depth of seven meters, and towed into harbor. Police searched it late Saturday and early Sunday.

"There are no persons in the submarine, dead or alive," Jens Moller, head of Copenhagen police's homicide unit, told a news conference Sunday.

He said it appears to have been deliberately scuttled, and is still being treated as a possible crime scene.

Madsen, an entrepreneur, artist, submarine builder and aerospace engineer, went before a judge Saturday behind closed doors for preliminary questioning. His defense lawyer, Betina Hald Engmark, said he denied the charges.

Police said Friday the inventor had told them he dropped Wall off from his submarine in Copenhagen on Thursday night. On Sunday they said they had since been given another explanation by Madsen, but declined to elaborate.

Police in Sweden said they had tried without success to contact Wall by phone and that her family had not heard from her.

The submarine, UC3 Nautilus, is one of three constructed by Madsen. It can carry eight people.