• The NTSB and FAA are working together to determine the cause of the crash
  • The bodies were found after a report at around 1.15 pm regarding a crashed helicopter northwest of Sacramento
  • The helicopter was a Robinson R66, a five-seat turbine copter

Four people were killed when a Robinson R66 crashed Sunday afternoon in Northern California, local authorities said.

Respondents from the Sacramento River Fire Division and Colusa County sheriff’s deputies discovered the bodies following a report at around 1.15 p.m. about a downed helicopter near Colusa, which is about 70 miles northwest of Sacramento, a statement from the sheriff’s office revealed, NBC reported.

According to a CNN report, deputies from the Colusa County Sheriff Department and fire personnel discovered all victims deceased on the scene. Their identities have not been released yet.

The Federal Aviation Administration (FAA) and the National Transportation Safety Board (NTSB) have launched an investigation into the helicopter crash.

NTSB spokesperson Jennifer Gabris said board investigators will “look at the human, machine, and environment as the outline of the investigation,” CNN reported.

The CCSD is speaking with witnesses who may have crucial information about the incident.

According to Gabris, the full investigation could take between 12 to 24 months for completion, but a preliminary report should be available from the NTSB after 15 days. The probe is expected to include data from air traffic control communications as well as the unidentified pilot’s medical records.

Plane Crash In this representational image, rescue workers and police are pictured at the site where two people were killed as a small plane crashed into a field in Furnes, some 100 km north of Oslo, Norway, Sept. 19, 2017. Photo: Getty Images/ FREDRIK HAGEN