In a Twitter message, Greenpeace said: "The first of the Arctic 30 has had the investigation against him officially dropped. Home is one step closer," RIA Novosti reported.
Russian authorities have not yet commented on the release.
The so-called Arctic 30, 28 activists and two journalists, were facing trial on hooliganism charges. They were arrested while protesting oil drilling the Arctic Sea, an environmentally sensitive area.
Russian President Vladimir Putin said last week the Greenpeace activists would probably be released under the amnesty bill.