COPENHAGEN — He said he was into S-and-M, but not with his submarine passenger. He said she died on board in an accident, and he buried her at sea because that was maritime tradition. And why did he initially lie to the police about what happened? He said he wanted to see his wife and his three cats.

Peter Madsen, a Danish inventor, was charged on Tuesday with the murder of a Swedish journalist, Kim Wall, who had boarded his submarine on Aug. 10 to interview him for an article.

Questioned by lawyers during a court appearance that lasted four and a half hours, Mr. Madsen furnished many details but did not answer an essential question: How did Ms. Wall’s mutilated body — she was missing her head, arms and legs — end up in a bay near Copenhagen, 11 days after she and Mr. Madsen set out on his 55-foot submarine?

Mr. Madsen’s insistence that he did not kill or dismember Ms. Wall was met with skepticism.

The judge, Anette Burko of Copenhagen District Court, said his account was “not reasonable.” She approved the prosecution’s request to upgrade the accusation against Mr. Madsen, who was initially charged with involuntary manslaughter, to manslaughter, which in Danish law implies intentional homicide and is the legal equivalent of murder. She ordered him held for an additional four weeks and scheduled him to appear in court again on Oct. 3.