"The only thing funnier than watching non-professionals trying to investigate an air accident, is watching dogs on youtube trying to chew toffee."
About the only things we know so far is that this aircraft 1) made a more or less ballistic dive into the ocean from about 11,000 feet, and 2) it appears to have done so in substantially one piece, which tends to rule out a major explosion.
And secondarily that there appears to be no communication. Although that is quite common - pilots try to save their lives by flying, not by telling ATC where to find the hole in the water (or ground).
That does not rule out (or in) a smaller explosion (accidental or intentional - no evidence yet), that perhaps disrupted hydraulic or control runs, or the cockpit floor, or the trim jackscrew - or something completely different. Not large enough to disassemble the airframe, but possible enough to render the controls inoperable.
There appear to be eye (or ear) witness reports of explosions (but read up on the reliability of eyewitnesses - it also make funny/sad reading).
But in any case, that is just one of many possible scenarios. Each one of which should rate an initial probability of 1% - until further evidence rules them out completely (probability = 0%) or does not. In which case they remain in the mix for continued consideration.