This means a central fuel tank explosion. Accordingly, one searches for the origin of the explosion, and this has not definitively been identified, so the investigation is still open. I understand that the first two have been identified in the case of TWA800, and have led to the extensive research into flammable fuel vapors in central wing tanks of commercial aircraft. The search for a competent ignition source is open. I understand these accidents are believed to have emanated from EMI-FBW interference.
Electrics are generally more robust than electronics.
There was no evidence of a pre-existing fire, a bomb or a missile found. Finally, one should note that an aluminium aircraft hull acts as a significant barrier in each direction to electromagnetic radiation on radio frequencies. The original response to questions of EMI from passenger electronics pointed out that the nav receiver antennae were outside the hull, but the potentially damaging signals were supposed to come from inside the aircraft, and no one could see a way that those signals could have interference strength outside - they simply couldn't be powerful enough. As far as I know, no one has published estimates of what the field strength would have to be outside the aircraft in order to create that requisite field strength within the aircraft hull sufficient to cause arcing in any component of the fuel gauging system, fuel pumps or other such systems. This leads to the following commentary on Scarry's three suggestions.