The NTSB's claim and evidence were controlled and directed by the FBI. I guess you explicitly trust the 'government' (even knowing today how crooked they have been all along) ?
Anyway, here is the Ringmaster with his positive proof.
This is the piece allegedly taken from the CWT where the "arcing of metal" allegedly occurred.
Remember, this particular piece would have been at the center of the explosion.
I can guarantee you that that piece of metal has never been in a fire and explosion.
Kallstrom was never qualified to lead an investigation into aircraft incidents, yet, he made claims teat were outrageous and with dictatorial authority that went unchallenged. He was a liar and a political stooge.