But he later told investigators that an accident on the submarine, which sank, had caused Ms. Wall’s death, and that he had buried her at sea.
Jens Moller, chief homicide investigator for the Copenhagen police, said at a news conference that metal had been attached to the torso to weigh it down. “We consider this a breakthrough in the investigation,” Mr. Moller said, “but we continue to search for the missing body parts.”
He also said that “coagulated blood” had been found inside Mr. Madsen’s submarine, which was recovered from a depth of about 22 feet. The police have said that they believe the submarine was deliberately sunk.
Mr. Madsen’s lawyer, Betina Hald Engmark, said after the police announcement that she and her client “only find it positive that there is a final clarification” about Ms. Wall’s body having been found.
“It is with boundless sadness and shock that we received news that the remains of our daughter and sister Kim Wall have been found,” Ms. Wall’s mother, Ingrid Wall, wrote on Facebook on her family’s behalf on Wednesday. “We cannot yet grasp the extent of this catastrophe and there are many questions that must be answered.”
Ms. Wall — a graduate of the London School of Economics and both the Journalism School and the School of International and Public Affairs at Columbia University — had been preparing to move to Beijing with her boyfriend. She planned to write about China and the region.
“The confirmation of the death of Kim Wall is a matter of deep sadness for the F.C.C.C.,” the Foreign Correspondents’ Club of China said in a statement on Wednesday. “Kim joined the club having recently returned to Beijing full of passion for the stories she planned to cover here. She was a talented freelance journalist, brimming with integrity, humanity and a deep interest in China and the wider region.”
Mr. Jensen, the newspaper editor, said the case had transfixed Denmark.
“It began with a crazy scientist who we thought was a victim, as his submarine disappeared accidentally with a Swedish journalist onboard,” he said in a phone interview. “Our emotions were completely turned around as he went from victim to possible perpetrator.”
Scandinavian television and literature often portrays the dark currents under the surface of countries famous for safety, happiness, free education and free health care.
The hideous discovery of the torso has already elicited numerous comparisons to the television crime series “The Bridge”; the first season of that show begins with the discovery of a mutilated female body on the bridge over the Oresund strait that connects Copenhagen with Malmo in Sweden.
The themes of the series include gender issues and border crossings, and the series plays out in the same places where Ms. Wall grew up, in southern Sweden, and died, in the waters around Copenhagen.
“I’m not at all comfortable with commenting or reflecting over real crimes in this way,” the scriptwriter, Hans Rosenfeldt, wrote in an email.
But Mr. Jensen, the newspaper editor, said the similarities were too obvious to ignore. Mr. Madsen had been well known in Denmark as a quirky if temperamental innovator who had worked on developing rockets and submarines.
“This is a story about the bright Nordic region where dark forces lurk underneath the surface of our well-kept welfare states,” Mr. Jensen said. “There is an undercurrent of evil, and that’s the noir also found in literature. But the submarine captain is not normal. He broke the norms with his rockets and submarines, and with his alleged crime he broke the norms again.”