The co-pilot "voluntarily" initiated the descent of the Germanwings flight that crashed into the French Alps and refused to open the door to the pilot who was outside the cockpit, the lead investigator said on Thursday.
"The co-pilot is alone at the controls," said prosecutor Brice Robin, recounting information gathered from the "black box" recorder. "He voluntarily refused to open the door of the cockpit to the pilot and voluntarily began the descent of the plane."