There has been no claim of responsibility for last weekend's three fatal shootings near the Freeport mine in Indonesia's Papua province.
The OPM separatist rebels have denied responsibility while the Indonesian military says the OPM was likely to be behind the shooting.
The Papua police chief, Bagus Ekodanto, has told the Jakarta Globe there is no evidence of any particular group having carried out the killings.
The investigation is being assisted by Australian police because one of the shooting victim was Australian.
The Papua police chief has meanwhile denied reports that bullets were removed from the body of the Australian.
The bullets are reported to be from the standard weapon used by the police and military.
The incident comes amid claims of dissent between the police and military after Freeport switched paying for security from the military to the police.
