By Tim Johnston
The US government has been accused of involvement in covering up the real culprits behind a fatal attack in Indonesia's Papua province in 2002.
The Indonesian army cleared itself of blame
Two American teachers and an Indonesian were shot dead near the Freeport mine during an ambush.
An FBI investigation concluded in June that Papuan separatists were behind the murders.
But a group of Indonesian rights groups now say other evidence points towards the involvement of the Indonesian army.
The two teachers and an Indonesian colleague were killed when a group of gunmen ambushed their cars on the way back from a picnic.
In June, the US Justice Department said their investigation had concluded the three were killed by Papuan separatists, but critics believe the Indonesian army was behind the killings.
An initial investigation by the Indonesian police pointed to army involvement, but the army investigated the allegations and found itself innocent.
In a statement released on Wednesday, three Papua-based NGOs accused the US Justice Department of ignoring key pieces of evidence that pointed to the army's involvement.
They say the man accused of the killings, Anthonius Wamang, was co-operating with the military at the time of the killings, and admitted getting ammunition used in the attack from army personnel.
The US Congress has made resumption of assistance to the Indonesian army dependent on a satisfactory outcome from the investigation.
The Indonesian NGOs accused the US government of suppressing the evidence against the army in the interests of resuming co-operation in the war against terror.
The US Embassy in Jakarta declined to comment on the allegations, which threaten to re-open old differences between Washington and Jakarta.