I've never read a conspiracy theory which included officials NOT claiming that they know exactly what happened and why. The core of any conspiracy theory is that the authorities are lying. Here the authorities claim to be baffled, which is not what they would do if they planned to lie.
But I know what the true believers will reply... "That's what they'll be expecting us to do!"
Not true. I expressed my conspiracy theory, which I still believe to be true, way back in this thread, and it has nothing to do with officials lying.