The 17-year-old had been found dead by relatives in January on a street bench in west Athens following a tip-off from the kidnappers who had helped bring him to Greece in the first place.

Police said that the teenager had been held captive from October 2010 and malnourished to force his family to make a payment of 5,500 euros ($7,200).

But even though the money was paid, the kidnappers demanded more, ANA said.

The police arrested a 24-year-old Pakistani man who allegedly conducted the ransom negotiations as a suspect and are seeking another seven, the agency said.

Greece, currently in the throes of a major economic crisis, is an important hub for clandestine migrants to Europe from Turkey and the Middle East.

Pakistan is one of the main countries of provenance.

Smugglers charge a high price to bring migrants and refugees to Greece by plane, speedboat or truck and those who survive a perilous journey usually end up heavily in debt to the gangs.

Overall, nearly 100,000 people were arrested in Greece last year for illegal entry or residence and authorities are going through some 30,000 asylum requests by migrants and refugees, according to officials. (AFP)