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The mystery of a missing ship embroiled in contradictory reports deepened Saturday, as investigators in Finland said a ransom demand was made for the freighter that vanished more than two weeks ago.

It wasn't immediately clear whether the request for money from the purported hijackers of the vessel, named the Arctic Sea, was legitimate.

Markku Ranta-Aho of Finland's National Bureau of Investigation told national YLE radio Saturday that "a ransom demand has been made and it was addressed to the shipping company which is based in Finland, and let's say it's a largish amount of money."

He did not give details.

The latest twist came after a Russian maritime Web site said that the Arctic Sea's tracking system had sent signals from the Bay of Biscay off the coast of France.

French Marines denied that was the case and echoed Friday's reports that said the ship is likely somewhere off West Africa around Cape Verde, about 2,000 miles south of Biscay.

The respected Sovfrakht maritime site said the ship's signal appeared on a tracking service about 4:30 a.m. EDT Saturday in the bay.

The site cautioned, however, that the Arctic Sea's Automatic Identification System equipment may not be on the ship itself anymore. The signal disappeared after about an hour, it said.

Hours later, French Marines spokesman Capt. Jerome Baroe said the signals in question had come from Russian warships that were heading from the Mediterranean to the Baltic Sea.

Those ships apparently are different from the vessels that the Russian Navy dispatched this week to search for the Arctic Sea.

The Russian Navy won't release any new information about the whereabouts of the missing freighter. Its precise location remains unclear and is likely not known.

The freighter, carrying a load of timber, has been missing since July 28 after passing through the English Channel.

Crew members had reported that the ship was attacked in Swedish waters on July 24 by up to a dozen masked men, who they said tied them up, questioned them about drug trafficking, beat them and searched the freighter before leaving.

Such an attack would have been unusual in European waters, and raised questions because it was not reported until the freighter had passed through Britain's busy shipping lanes. There have been fears that some of the attackers might still be aboard, or that the ship came under attack a second time.

Radio messages from the freighter were later picked up along coasts of France and Portugal, but efforts to pinpoint the Arctic Sea's whereabouts have been difficult in the vast Atlantic and with no communication from the ship's 15-member Russian crew.

Cape Verde authorities said they had no new information Saturday, though Russia's ambassador to the country, Alexander Karpushin, said there was no confirmation the Arctic Sea had been found.

Baroe said it is "extremely probable" that the ship is off Cape Verde. He said the French Marines operational center in Brest had received no information indicating the ship is off the French coast, and so has launched no search in that area.

The Arctic Sea, which left from Finland on July 23, had been due to make port Aug. 4 in Algeria with its $1.8 million haul of timber.

The European Commission suggested the ship may have come under attack a second time off the Portuguese coast, spokesman Martin Selmayr said Friday.

Portugal's Foreign Ministry said, however, that the ship was never in Portuguese waters.

The ship's operator, Solchart Arkhangelsk, said it had no information about a possible second attack. It said the Arctic Sea's captain was 50-year-old Sergei Zaretsky, a veteran of such sea voyages, and the sailors were from the northwest Russian port city of Arkhangelsk.

Speculation on what might have happened to the ship has ranged from suspicions that it was carrying secret cargo — possibly narcotics — to theories about a commercial dispute. Security experts have been wary of attributing its disappearance to bandits, noting that piracy is almost unheard of in European waters.

"It would seem that these acts, such as they have been reported, have nothing in common with 'traditional' acts of piracy or armed robbery at sea," Selmayr said.

The Associated Press contributed to this report.