Initially the navy said the 40-ton, nearly 18-meter-long (60-foot-long) UC3 Nautilus was "found sailing" south of Copenhagen. However, navy press spokesman Anders Damgaard later said it had sunk and Peter Madsen, who built the vessel that was launched in 2008, had "been taken over to one of our ships." He declined to give details.
Footage aired on Denmark's TV2 channel showed Madsen, 46, getting off what seemed to be a private boat and making a thumbs up sign as he walked away. It was not clear why the submarine sank.
"He told us that the journalist who also had been on board had been dropped off Thursday evening," Damgaard told The Associated Press. Swedish media said the reporter was Swedish. "They were the only two on board yesterday."
After the submarine was reported missing early Friday, the navy had launched a search from Copenhagen to the Baltic Sea island of Bornholm with two helicopters and three ships, and encouraged members of the public with boats and sonar to search too.
"He told us he had technical problems" to explain why the submarine failed to respond to radio contact, Damgaard said.