Re Wunwing's Post
I agree totally with he has suggested, that is, nothing has been definitely proved as yet. Yes it certainly does appear, that someone could not obtain access from the cabin to the F/D, are we absolutely sure beyond all doubt, this was the Captain & not the F/O for example. As with so very many serious aircraft accidents / incidents, there are very many individual factors involved in the lead up to the event. The only people who really know what happened, are of course not able to tell. So, even with the information gathered so far, yes it looks likely that certain events happend & certain actions were taken, but there is surely, much more information & data yet to come to hand.