A single heat flash was detected by IR satellite at a time and location indicating a mid-air explosion of some sort.
Since the wings appear to have remained attached to the fuselage, it would seem to suggest that the fuel tanks did not explode until hitting the ground -
Was the heat flash confirmed as occured where plane was still in the air? Because even with the big bang at cruising altitude, I'd expect much bigger heat signal from fuel burning when plane crashed onto the ground.