Two of the accused have been remanded in custody until 26 August 2019 for mention.
Police said they would not release further details due to the seriousness of the allegation and the investigation is ongoing.
The matter was reported to Samoa Police Service on 13 August following a tip-off by the Lauli’i Village Council.
Police said their evidence includes the use of social media both inside and outside of Samoa.
They said they take the threat very seriously and that the full weight of the government's law enforcement is being used to thoroughly investigate the matter.
Police said they are seeking help from international partners, and that further arrests could be made.