ST. PETERSBURG, Russia - Russian investigators have dropped charges against all but one of the 30 crew of a Greenpeace ship who were accused of hooliganism after a protest outside a Russian oil rig in the Arctic, the group said Wednesday.

Cristian d'Alessandro of Italy failed to get his case closed due to the lack of an interpreter and will have to visit the St.Petersburg branch of Russia's Investigative Committee again Thursday, said Violetta Ryabko, a Greenpeace spokeswoman.

The charges against the crew were closed under an amnesty passed by the parliament earlier this month, seen by many as an attempt by the Kremlin to dampen the criticism of Russia's human rights before the Winter Olympics in Sochi in February.

Ryabko said crew members had already applied to Russian authorities for exit visas to leave Russia and expect to get them in the next few days.

The 30 crew members aboard a Greenpeace ship were detained in September and held in custody for two months before they were released on bail in November. They were originally charged with piracy, but that was downgraded to hooliganism.

"That was an extremely odd Christmas morning," Frank Hewetson of Britain was quoted by Grenpeace as saying Wednesday.

Peter Willcox, the U.S. captain of the Greenpeace ship Arctic Sunrise, said in a statement that he was "pleased and relieved the charges have been dropped, but we should not have been charged at all."