COPENHAGEN, Denmark (AP) — Police from Sweden assisted their Danish counterparts on Tuesday with pursuing leads in the search for a missing Swedish woman who was on an amateur-built submarine the night before it sank, while volunteers and authorities combed the countries' waterways for signs of her.
The submarine's Danish owner, inventor Peter Madsen, was questioned after the UC3 Nautilus sank Friday. Police later arrested Madsen on preliminary manslaughter charges in the disappearance of 30-year-old freelance journalist Kim Wall.
Madsen has denied having anything to do with Wall's disappearance. He told police that she disembarked from the submarine several hours into their Thursday night trip and he doesn't know what happened to her after that.
Danish authorities haven't said why they filed the manslaughter charges, whether they are searching for a body or if they expect to find Wall alive. She was on the submarine for a reporting assignment, according to her family.
Madsen was rescued from his sinking submarine in the Oresund strait, a narrow waterway between Denmark and Sweden that connects the North Sea to the Baltic Sea. Danish police said they suspect that Madsen deliberately sank the vessel, though he initially blamed technical problems.
Swedish police spokesman Mattias Sigfridsson said Tuesday that authorities in Sweden are providing details about people and places that could be useful to investigators in Denmark, but declined to be more specific.
But he urged the public to "pay attention to what is in the water."
"If you see things that seem normal, something resembling junk, look again, and contact us if needed," Sigfridsson told a news conference.
Copenhagen police said in a statement that "nearly 300 people" have contacted Danish investigators. Many of them had photographs and videos of the Nautilus as it sailed into the Oresund strait, according to the statement.
Sigfridsson said the main probe is in Denmark, where investigators continue searching for Wall. The Nautilus was hauled up from a depth of 7 meters (23 feet) on Saturday, but the woman's body was not inside it, police said.
Submarine experts from the Danish navy have assisted police in searching the submarine, which is standing on land in a cordoned-off, industrial area in northern Copenhagen. Investigators have finished the technical investigations "as well as an actual search of the submarine," the police statement said Tuesday.
"With regard to the continued investigation, we are currently unable to provide information about what was discovered at the examination and search," police said.
Copenhagen police said they also had received information that the submarine "was close" to a merchant ship around midnight between Thursday and Friday. Local media have reported that the submarine was spotted close to a ship with all its lights off. It was not clear whether the police were referring to that incident.
The 40-ton, nearly 18-meter-long (60-foot-long) submarine sank off Denmark's eastern coast. A Danish military plane, requested by police, has been flying for the past few days over the Oresund straight.
In Sweden, volunteers explored the country's coast for signs of Wall. Boats belonging to the Sea Rescue Society sailed along southwestern Sweden searching for clues.
"We are hoping to find something," the group's spokesman, Fredrik Winbladh, told Sweden's TV4 channel. "We are doing what we can ... we will never give up."
The Nautilus set out from Copenhagen's harbor late Thursday. Denmark's navy launched a search early Friday after the submarine hadn't returned to Copenhagen as expected. The search involved two helicopters, three ships and several private boats. The navy said the sub was seen sailing, but then sank shortly afterward.
On Saturday, a Copenhagen court ordered Madsen held in pre-trial detention for 24 days while police investigate the case.