In a puff of smoke?

So it's now over four years since Flight MH370 took off from Kuala Lumpur bound for Beijing and simply - disappeared.  The Malaysian government have released what they say is their final report on the matter, and which concludes that they have no idea what happened or why.  Of course, there are those who are not prepared to leave it at that.  The French police - there were four French on board - have said they are going to open their own investigation and others may follow their example.