NTB doesn't normally investigate foreign carriers in foregn countries.. The following from the NTSB website:
DCA97RA001
This accident is under the authority of the Director General Transport Aereo. Contact Ricardo La Puente, DGTA, Av. 28 de Julio No. 800, Lima, Peru.Telephone 511-433-3166, FAX 511-433-2808.
The official accident report from the government of Peru was issued by the DGTA for the Commission of Accident Investigations on January 17, 1997. The report is in Spanish, and is contained in the public record portion of this accident file. All annexes and any other supporting data must be obtained from the DGTA.