Actually, there's tons of preliminary evidence that it was a bomb and absolutely no preliminary evidence that it was an accident.
These people had better not dare to start to cover this up.
Scads of people saw and explosion and the engine and debris fall off, there is video footage of the engine lying on the ground intact away from the crash site.
The strange thing is that the Administration, at least, is saying they have no evidence one way or the other while the usual suspects say all the usual preposterous things.