Moscow - Russia on Wednesday dropped all but one of the cases against 30 crew members of a Greenpeace protest ship, marking the "final chapter" in a three-month criminal probe, the environmental group said.The cases were dismissed under a Kremlin-backed amnesty that specifically mentioned the charge of hooliganism levelled against the environmental campaigners. The detention of the group sparked global protests and tainted Russia's image ahead of February's Winter Olympic Games in Sochi.Twenty-five foreigners were summoned to the investigative committee on Wednesday to receive confirmation that the hooliganism probes launched after their September protest against oil drilling in the Barents Sea had been dropped, Greenpeace said. Only Italian activist Cristian d'Alessandro failed to receive the relevant paperwork. Greenpeace said the delay was due to the absence of a translator and the Italian was invited to return on Thursday.Anthony Perrett of Britain was the first Greenpeace member to have his case dismissed on Tuesday.The four Russian crew also benefitted from the amnesty."The final chapter in the legal ordeal of the Arctic 30 began today," Greenpeace said in a statement.The next step will see the foreigners receive exit visas to leave Russia "in the coming days," Greenpeace said. Five people come from countries that have a no-visa regime with Russia. But "they also need the migration service sticker to leave," said spokesman Ben Stewart.'Pleased and relieved'The group said it also expected Russian investigators to release all the equipment seized during the raid of the Arctic Sunrise, as well as the ship itself, which is still impounded at Russia's Arctic Circle port of Murmansk.Arctic Sunrise was boarded by Russian border guards and towed to Murmansk in September after several activists attempted to scale the Prirazlomnaya oil rig belonging to Russian energy giant Gazprom to protest Arctic drilling.The crew then spent several weeks detained in the local jail before being transferred to Saint Petersburg and released on bail. Originally facing a charge of piracy, they were later left with only the less severe hooliganism accusation.Greenpeace argues that the group's detention was illegal as the ship was in international waters. Russia however said it was in the right and needed to protect its platform, while President Vladimir Putin slammed the group for merely seeking publicity.An international maritime court in Germany in November told Russia to release the activists and the ship in response to a formal complaint lodged by the Netherlands, under whose flag the ship sailed.But Russia boycotted the German court hearings and ignored the ruling.The ship's US captain Peter Willcox on Wednesday said he was "pleased and relieved the charges have been dropped".But some activists said the amnesty document merely lifted the investigation and punishment while still recognising their peaceful protest as a crime.In a further upset to the group, Gazprom last week announced that it had started oil production at the platform, formally launching its first offshore production in the Arctic.