The chief Marseille prosecutor handling the investigation into the horrible crash of the Airbus A320 in a remote area of the French Alps on Tuesday alleges on Thursday that evidence from the cockpit voice recorder indicated that the co-pilot who was left in sole control of the Airbus after the captain left the cockpit, refused to re-open the door and pressed a button that sent the jet into its fatal descent.  Thus it seems that the co-pilot was conscious and deliberate in his actions. It is however not clear why he did so.