If the pilot went to take a leak and was overpowered, and the copilot left the door open, it would explain a lot, including the last radio communication, which was mumbled and unintelligible. It would also explain why the transponder was switched off. It appears it may have been if there’s no record of the plane after the turn, and no debris.
I don’t understand the purpose of a terrorist act that remains unclaimed and unknown. I’m not saying that it couldn’t be. It just seems odd that there would be no claims of responsibility. The purpose of terrorism is to create terror, right?
Most likely scenario at this point is sudden jihadi syndrome by one of the pilots or a bomb. I would look real close at the co-pilot.
Just wondering: Is there a legitimate reason why the transponder of a commercial airliner is allowed (has the capability) to be shut off?