(CNN) -- A medical helicopter crashed early Saturday near Doyle, California, killing all three people on board, a Federal Aviation Administration spokesman said.

Ian Gregor said the Aerospatiale AS350 helicopter was returning to Susanville, California, from dropping a patient in Reno, Nevada, when it crashed near Doyle around 2 a.m.

All three people on board the helicopter, which was operated by Mountain Life Flight, were crew members, Gregor said. He said the crash impact and subsequent fire destroyed the aircraft.

It was not immediately known what caused the crash.

FAA and National Transportation Safety Board investigators will be on the scene on Saturday, Gregor said.

Doyle is about 45 miles northwest of Reno.