He identified the pilot as Andreas Lubitz, a German national and who had never been flagged as a terrorist. He stated Lubitz appeared to want to "destroy the plane."
Lubitz was described by acquaintances in his hometown of Montabaur as a "normal guy" and "nice young man".
"He was a completely normal guy," Klaus Radke, the head of the local flight club where Lubitz received his first flying licence years ago. He returned in the fall for a refresher course with Radke.
"I got to know him, or I should say reacquainted with him, as a very nice, fun and polite young man," Radke added.
The small town of 12,000 in western Germany was in shock on Thursday at the news that French prosecutors suspect Lubitz, 28, of deliberately crashing the Airbus plane.
German authorities were at loss to explain why the first officer for Lufthansa's budget carrier appeared to have taken sole control of the A320 airliner when the captain was out of the cockpit and slammed it into a fatal descent.