A US-based group, Human Rights Watch, has condemned last Saturday's killing of three teachers, including two US citizens, near the Freeport mine in Indonesia's Papua province.
The group has urged Indonesia to get independent experts to investigate the killings, adding that only an independent probe would have credibility with local citizens and internationally.
It also says the company running the mine should co-operate.
The Indonesian military has accused the separatist OPM group of the killings but the OPM has rejected the claim.
And the head of the Indonesian police says they have been unable to conclude whether the killers were OPM members.
Meanwhile, Australia is reported to have offered to help the mine owners find replacement teachers for the three who were killed.
A diplomat sent to Papua has described the province as one of the most secure areas of Indonesia.
He told The Age newspaper that the travel advisory warning has not been upgraded, saying this would increase insurance costs and make it more difficult to attract staff.