Reports in the American press indicate that FBI agents believe evidence was planted as part of the investigation into the attack on teachers near the Freeport mine in the Indonesian province of Papua.
Three people died..two Americans and one Indonesian and up to ten others were wounded when the convoy they were travelling in was fired on.
The military has blamed the attack on separatists, but the Indonesian police and those representing the Free Papua Movement have accused the army of being involved.
Now a report in the Washington Post, says the FBI investigation has led agents to believe that soliders tried to plant false evidence.
But the agents have also cast doubt on the credibility of a witness in police custody who claims to have first hand knowledge of military involvement in the killings.