The wing stalled....that seems pretty obvious to many here. It was certainly not a deliberate roll to the left, the aircraft simply isn't capable of such a rate of roll.
For those who favour the VMCA theory I strongly disagree. Reducing IAS through VMCA would never produce such a high rate of roll. For certain one wing stalled, and quite likely very shortly after so too did the other one.
A tragedy, and for those fortunate enough to survive, also miracle.