The public prosecutor in Basel, Switzerland, has opened a probe into the kidnapping of 12 seafarers from a Massoel Shipping bulker off Nigeria.
The crew were abducted from the 47,000-dwt Glarus (built 2001) last month off Bonny Island.
Talks with the kidnappers are ongoing, the Swiss daily SonntagsBlick reported.
The men include seven Filipinos, a Croatian, a Bosnian, a Slovenian, a Ukrainian and a Romanian.
Switzerland's Massoel Shipping told SonntagsBlick that the crew were doing as well as could be expected, given the conditions.
The gunmen are reportedly from the Movement for the Emancipation of the Niger Delta (MEND).
Seven crew were not taken in the attack.
