Chronus:
Surely the authorities must by now have more information . The question is if they do. then why are they keeping it under wraps. It follows that entertaining such thought will inevitably lead to even more speculation of all manner of skullduggery and mischief.
You cannot base a logical conclusion on "negative evidence".
Despite the best efforts of the fantasists who appear on Pprune after every incident, there is nothing that can yet be deduced from ACARS, the last minute of the flight path or the absence of communication except that the aircraft and/or crew had something happen to it and it went in the water.
Furthermore, the truth, if it is ever discovered, may be quite a bit stranger than the uninformed speculation here.
Furthermore again, the question of positively locating every commercial jet while in flight is not trivial, neither is finding a wreck on land or water.
There are no quick easy cheap solutions despite what some may think.