An officer from the Federal Bureau of Investigation is among a group of American security officials now in the Indonesian province of Papua to investigate last weekend's ambush.
The attack left three teachers dead, including two Americans, and injured more than half a dozen others.
The Indonesian military has blamed the attack on members of the Free Papua Movement and the Jakarta Post says it has already finished its search for those behind the shootings.
But the rebels have denied the accusations and say it is more likely that the military were involved some how.
Australian consular officials from the Australian Embassy in Jakarta are also in Papua to assess security conditions at the Freeport mine and to meet Australians working there.