There has been so much conflicting information coming out it's impossible to say what happened. Did it even actually turn back?

There could be a lot of political face saving going on here, when it comes to releasing data. Remember the Egypt Air crash, where the copilot locked the Captain out of the **** then dove the 767 into the ocean? For months the Egyptians tried to blame Boeing and the 767 for that.

If it did turn back, why, and how far did it really get before it either hit the water or went down in the jungle?

If not, and it went down near where the transponder stopped working, where's the debris field?

When I first heard about it, my guess was they had a short in the Electronics compartment, which is below the ****. That would explain why the transponder(s) and radios quit working, that would explain the turnback. You don't fly into China with no radios or transponder, unless you want to be shot down.

OK, so say they had such a problem, turned back, but then the problem escalated to a full blown fire in the E/E compartment. Now what? They would be getting smoke in the ****.

They cannot simply go down there and spray it with an extinguisher. But they would want to descend to a lower altitude (below 10,000') and turn off the pressurization, to keep the smoke from circulating.

Now say the fire is out of control and it eventually renders the airplane unflyable. The 777 uses a 'fly by wire' flight control system, electrons tell the hydrolic actuators what you want it to do, but with zero electrics, not so much.

The crew may have been overcome by the smoke when their oxygen ran out, and the airplane did a slow descent into the sea or jungle, if it got that far.

Remember, this happened at 2am. Pitch dark out over the water, no witnesses other than maybe a fishing boat, but at 2am, they were sleeping too, and seeing an airplane in the dark is pretty hard if the position lights aren't working.

If it blew up inflight, due to a bomb or a meteor strike, there would be floating seat cushions, luggage and bodies all over the place.

If the crew was able to set it down gently on the water, ala Sully on the Hudson, (highly doubtful at night) the airplane would eventually fill with water and sink. Again, this was 2am local, it might have floated for a few hours, but still gone under before anyone (like Fishermen) was able to spot it. There are huge 20 man life rafts at every door however, and those would have been deployed and spotted by now, I would hope.

Unless they didn't put it down so gently, and everyone was dead on impact, and it sank. Still, there should be some debris floating by now.

I'm going with Aliens.