Nothing you posted has anything to do with what I asked you. No legitimate investigation determines anything prior to investigating, that is the purpose of every single investigation, to figure out what happened, not to assume what happened. In this case, it was the worst terrorist massacre in modern history, there is no excuse for failing to investigate EVERYTHING, especially to fail to chemically analyze the evidence as required by standard fire investigation protocol. Your opinion that "for most experienced architects and engineers, the reasons why the WTC collapsed was pretty clear" is not only irrelevant but is speculative at best and wrong at worst. Many question the WTC collapses and the ensuing investigation, some find it illegitimate and part of the reason why is what I stated (see underlined).