The evidence does seem to be getting stronger, but I'm not quite ready to conclude that this was intentional. The fact that the co-pilot was breathing does not necessarily indicate that he was conscious. If he became unconscious, he could easily have fallen into a position where his body was pushing forward on the control stick. This would override the autopilot and cause the plane to descend under "manual" control. As far as I know, they still haven't found the FDR, so there's really no way to tell whether or not the "manual" control inputs were intentional (i.e. varying inputs with relatively light pressure would probably indicate intentional control; relatively continuous inputs at an extreme input position would probably indicate unintentional input). The locked cockpit door is harder, but not impossible, to explain: I'm not familiar with the design of the switch, but it's conceivable that he could have fallen against it and knocked into the locked position; perhaps more plausibly, he may have recognized that he was about to pass out (I have personally fainted due to low blood sugar a few times, and it generally doesn't happen without at least a few seconds of advanced warning) and, attempting to turn the switch to the "unlocked" position in order to simplify a hasty ingress of the captain, may have inadvertently turned the switch in the wrong direction. Before we vilify this guy posthumously, let's make sure we have precluded all other options.