This is now officially a criminal investigation, as reported in The Washington Post.  The Airliner’s ACARS system initiated periodic “handshakes”with comm satellites approximately every 30 minutes for an additional seven hours after civilian radar contact was lost.  The plane’s location could not be ascertained from the signals and it is not known whether the plane was in flight for the duration of that time or if it had landed, nor is it clear whether it crashed or was landed and shut down when the system stopped communicating.

The exact amount of fuel on board is not known, but it would  have been sufficient for the scheduled six hour flight to Beijing and common practice is to carry a minimum 1 hour reserve.  Authorities have several working theories, mainly falling along three lines.  First is that the plane was hijacked either by the crew or terrorist passengers and then crashed intentionally into the Indian Ocean as an act of either terrorism or suicide.  Another theory is that the plane was hijacked by either crew or passengers with the intent to divert and land at an unknown location, but then ran out of fuel and crashed.  The final theory is the same as the second theory except that in this scenario the plane was successfully landed at an unknown location.  This third theory is deemed the unlikeliest, since authorities believe that for this to happen, the plane would have been detected entering either Indian or Pakistani airspace and as of yet there is no indication that this occurred.

Additional information:

ABC News (autoplay video)


UK Daily Mail