No body has been found in the wreck of a submarine whose inventor is accused of the manslaughter of a woman said to have been board when it sank on Friday.
"The sub has been searched and there is nobody on board — neither dead nor alive," the chief of homicide for the Copenhagen police, Jens Moller, said on Sunday.
The missing woman, Swedish journalist Kim Wall, 30, was writing a feature about submarine's inventor Peter Madsen, 46, and boarded the vessel with him on Thursday evening.
Mr Madsen, who was rescued after the submarine sank, has been accused of manslaughter and remanded in custody for 24 days. He denies the allegation and says he dropped Wall off on the Refshaleoen island on Thursday evening after the interview.
The 18-metre submarine, the Nautilus, was refloated and towed to the Copenhagen port on Saturday, then emptied of water overnight. On Sunday police entered the sub and found it empty.
Nothing has been heard from Wall since she boarded the submarine. Her boyfriend alerted police early on Friday that she had not returned home as planned. Danish authorities then announced they were looking for the Nautilus in waters off Copenhagen.
The vessel was located in a bay in Koge, some 50 kilometres south of the Danish capital, around midday. Just after being located, Mr Madsen was rescued and the submarine suddenly sank.
He has said the submarine developed a problem with the ballast tank.
However, Mr Moller said on Sunday it appeared it was a "deliberate action that caused the sub to sink", amid media speculation that Mr Madsen may have been trying to cover up a crime.
"We're still hoping that we'll find Kim Wall alive, but we are preparing ourselves for the fact that she may not be," he said.
Wall is a freelance journalist based in China and the United States. Her articles have appeared in the New York Times and the Guardian, among others.
Mr Madsen made headlines when he launched the Nautilus in 2008, at the time the world's biggest homemade submarine.