LONDON (AP) -- First the ship reported it had been attacked in waters off Sweden. Then it sailed with no apparent problems through one of the world's busiest shipping lanes. And then it disappeared.
The Arctic Sea, a Maltese-flagged cargo ship, was supposed to make port in Algeria with its cargo of timber on Aug. 4. More than a week later, there's no sign of the ship or its Russian crew.
Piracy has exploded off the coast of lawless Somalia - but could this be an almost unheard of case of sea banditry in European waters?
"If this is a criminal act, it appears to be following a new business model," Marine intelligence expert Graeme Gibbon-Brooks told Sky News on Wednesday.
Russian President Dmitry Medvedev ordered the country's defense minister on Wednesday to take "all necessary measures" to find the missing cargo ship and, if necessary, to free its crew, the Kremlin said. Wives and other relatives of the crew members issued an appeal to the Russian government to carry out a full-scale rescue mission, using all of Russia's special services.
The mystery began on July 24, when the 15 crew members of the Arctic Sea said they were tied up and beaten by a group of up to 10 men who boarded the ship off the Swedish island of Oland. The masked men identified themselves as police officers - but Swedish police said they hadn't been searching ships in that area.
Swedish police investigator Ingemar Isaksson said the crew then claimed that the men left the ship 12 hours later in a high-speed inflatable boat.
"We were very puzzled when we first heard about this," Isaksson said then. "I have never heard of anything like this in Swedish waters."
On July 28, the Arctic Sea made contact with British maritime authorities as it passed through the busy English Channel. The ship made a routine, mandatory report - saying who they were, where they were from, where they were going and what their cargo was. It appeared routine, said Mark Clark of Britain's Maritime and Coastguard Agency.
He said the agency is "extremely curious" about what happened to the ship.
"It's bizarre," he said. "There is no coastguard I know who can remember anything like this happening."
Where the ship was next spotted is uncertain. Russian media reports say the last contact was on July 30 when the ship was in the Bay of Biscay, and that it was later spotted by a Portuguese patrol plane, but there was no contact.
But Portuguese Navy spokesman Commander Joao Barbosa said "we can guarantee that the ship is not in Portuguese waters nor did it ever pass through Portuguese waters."
The cargo was shipped by Finnish wood supplier Rets Timber, and is worth 1.3 million euros ($1.84 million), the company said.
"We have no idea where the ship is," company managing director Kari Naumanen told the AP in Helsinki.
Experts are very concerned about the vessel and crew, but at the same time are wary of attributing the disappearance to armed bandits.
"There have been no attacks in European waters," said Pottengal Mukundan, director of the London-based International Maritime Bureau. "It's not the kind of area where pirates would find it easy to operate."
Nick Davis, the chief executive of the Merchant Maritime Warfare Centre, told the BBC that if anything had happened to the ship, cargo would have been found.
"I strongly suspect that this is probably a commercial dispute with its owner and a third party and they've decided to take matters into their own hands," he said Wednesday.
Pirate attacks off Somalia's lawless coast are a far more familiar occurrence. Pirates have launched more than 100 attacks this year in the Gulf of Aden, one of the world's busiest shipping lanes, and are currently holding about a dozen vessels.
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