Vixen
Penultimate Amazing
No, that was expressly not what was asked. The hypothetical asks what we should conclude about the collapse of the building in light of a conflict between witness statements and circumstantial evidence.
The fact that you invented a new question that smacks of character judgment illustrates why you are the wrong sort of person to be second-guessing the work of professional investigators. Concluding that a witness may have been mistaken on some point is subtly different than commenting upon a witness' reliability.
Look. All an eye-witness can report or should report is his or her own observations. It is not an eye-witness' job to determine what caused an accident. If an eye witness says he or she heard a bang, then you can't know that they were mistaken because they might have done. This is why what-if scenarios are such a waste of time because you are now going to come back and say: 'See! Told you so! There were no explosives int he what-if scenario, so those eye-witnesses were real duds when it came to eyewitnessing!'