4U9525. Lubitz' "deliberate attempt to destroy the aircraft."* **

"The co-pilot [Andreas Lubitz] is alone at the controls," [Marseille] prosecutor Brice Robin said, drawing on 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."
http://www.telegraph.co.uk/news/worldnews/europe/france/11496066/Andreas-Lubitz-and-Patrick-S-What-do-we-know-about-the-pilots-on-Germanwings-flight-4U9525.html

*UPDATED, 1:08 pm UTC. He added: "The most plausible interpretation is that the co-pilot through a voluntary act had refused to open the cabin door to let the captain in. He pushed the button to trigger the aircraft to lose altitude. He operated this button for a reason we don't know yet, but it appears that the reason was to destroy this plane."http://www.bbc.com/news/world-europe-32063587

**UPDATED, 1:18 pm UTC. "Deliberate attempt." http://www.cnn.com/2015/03/26/europe/france-germanwings-plane-crash-main/