Germanwings co-pilot wanted to destroy the plane

The Airbus 320 from Barcelona to Duesseldorf hit a mountain in the Alps, killing all 144 passangers and six crew, after an eight-minute descent.
Andres Lubitz, the germanwings co-pilot, appeared to want to destroy the plane. The black box say that the co-pilot was alone in the cockpit. 

During the travel, the pilot, Patrick S, goes to the WC and let the co-pilot alone in the cockpit. When he return the door was closed. Nobody heart anything inside the cockpit. They try to open the door but they couldn't. Eight minutes later the plane crashed in the Alps. 

There's no indication that the co-pilot became physically ill or suffered a stroke. 

http://edition.cnn.com/2015/05/06/europe/france-germanwings-crash-report/