The National Forensic Service is helping identify the South Korean victims of a deadly helicopter crash in Peru last week as local authorities struggle to complete the task on dental records alone.

Peruvian authorities and the South Korean Embassy in Lima decided to call on the National Forensic Service since only four of the eight South Koreans killed in the crash have been identified. They sent photographs of the victims’ bodies, hands and face to the forensic agency in South Korea.

The South Korean Embassy said that the aviation accident investigation commission under the Peruvian Ministry of Transportation and Communications is investigating what caused the chopper to crash in the Andes. The embassy said the commission is likely to take at least three months or a year at the most to release the results of its probe.

Meanwhile, 16 family members of the eight South Koreans killed in the crash arrived in Cusco where the bodies have been moved. The family members received explanations on details of the accident and progress that has been made in identifying the bodies.