What Became of the Physical Evidence of the WTC Attack?
Ground Zero was sealed off and mopped up with astonishing speed. Some photographs of it survive in spite of authorities' efforts to prevent documentation of the crime scene.
Virtually none of the physical evidence of the horrific crime of the September 11th attack on Lower Manhattan survives.
Had the towers remained standing, much of the evidence of the attack's first installment -- the aircraft impacts -- would have survived the disaster (if not subsequent handling by the authorities). Even though the planes were largely shredded on impact, forensic analysis could have confirmed whether they were really Flights 11 and 175, as opposed to other aircraft.
The "collapses", however, assured that the aircraft remains would be degraded beyond recognition; or at least that no one would expect investigators to recover them. It also made more plausible the official story that the black boxes were destroyed or damaged too badly to yield data.
The "collapses" created their own evidence: The pile of twisted steel columns and girders at Ground Zero held the clues to what were, based on the official explanation, the three largest and least understood structural failures in history.
Since no steel frame high-rise building had ever been leveled by any cause other than controlled demolition or severe earthquakes, the total collapses of Buildings 1, 2, and 7 of the World Trade Center would seem to warrant the most painstaking forensic analysis.
Instead the structural steel was removed and recycled with astonishing speed, while volunteer investigators were hampered by red tape and access restrictions.