Originally Posted by
Uplinker
There is no way of knowing which pilot selected the altitude or the descent mode*, unless they took manual control^, which is unlikely.
* There is just one knob to do this, (well, two if you include V/S), but both pilots use the same control(s) depending who is PF.
^ Then we could see which sidestick was moved.
I wouldn't expect the sidestick to be used if you dial in a lower altitude. It is irrelevant anyway because the CVR confirms who was left alone in the Flight Deck.