The Investigative Committee's statement today is further indication that Russia is determined to prosecute the environmental activists — including two Canadians — for the Sept. 18 protest at the oil platform.
All 30 people who were on board the Greenpeace ship, a group that also included two journalists, have been jailed for two months pending the investigation.
Canadian crew member Paul Douglas Ruzycki, of Port Colborne, Ont., was serving as the ship's chief mate, and Montrealer Alexandre Paul, 35, was also on board.
The Investigative Committee said charges would be filed soon, but did not specify whether it is still considering charging the activists with piracy, a crime punishable by up to 15 years in prison.
The investigators said they are continuing to search the Greenpeace ship, the Arctic Sunrise, and have seized some equipment and documents.