I believe the 78 year old captain at 4:00 AM was not flying. I think that is the probable cause of the accident. The autopilot failed and he couldn't fly it like my buddy who couldn't control our flight into LAS.
That is an likely probable cause for sure. While from the photos from the accident site shows very little wreckage to work with, as I learned in NTSB Aircraft Accident Investigators school, the NTSB can find out a hell of lot with very little material. But some, it is just impossible to find the cause, there is just not enough left.
And I will very surprised if the CVR was working.