Presumably it's possible for the Indonesian authorities to make a good guess as to who was flying the plane at the time, as I imagine whoever asked for FL380 wasn't the PF, and the accent should be fairly easy to identify (Indonesian vs French)?
Also - and echoing an earlier post - no information has come out about the cause of death identified in the bodies brought back to shore. Distressing as it is to the families, the condition of the bodies may be an important clue as to what happened to the plane.