DOYLE, CALIFORNIA (BNO NEWS) — A medical helicopter crashed near the California-Nevada border on Saturday morning, killing three people on board, federal officials said.

The crash happened around 2 a.m. local time about 11 miles south of Doyle, an unincorporated community in California’s Lassen County. It is located about 45 miles northwest of Reno, Nevada.

Three people were on board the Aerospatialte AS350 helicopter when it crashed under unknown circumstances, said Ian Gregor, a spokesman for the Federal Aviation Administration (FAA).

Gregor said the helicopter was en route from Reno to Susanville, California when the crash occurred. The helicopter had dropped a patient off at a hospital in Reno just before the crash occurred.

“The aircraft was destroyed by the crash impact and fire,” Gregor said. It is believed all three victims were crew members, and that no patients were on board. The pilot was not communicating with air traffic controllers when the accident occurred.

The 1982-build rotorcraft was registered to Mountain Lifeflight, located at Susanville Airport.

The Federal Aviation Administration (FAA) and the National Transportation Safety Board (NTSB) will investigate the cause of the crash.