I have no friggin' clue.
But here's some of the latest information:
On May 20th 2016 The Aviation Herald received information from three independent channels, that ACARS (Aircraft Communications Addressing and Reporting System) messages with following content were received from the aircraft:
00:26Z 3044 ANTI ICE R WINDOW
00:26Z 561200 R SLIDING WINDOW SENSOR
00:26Z 2600 SMOKE LAVATORY SMOKE
00:27Z 2600 AVIONICS SMOKE
00:28Z 561100 R FIXED WINDOW SENSOR
00:29Z 2200 AUTO FLT FCU 2 FAULT
00:29Z 2700 F/CTL SEC 3 FAULT
no further ACARS messages were received
There is also speculation that the dive, 360 degree turn and plunge was probably large sections of the aircraft that could be seen by radar.