It probably was, but the overwhelming evidence of squibs and nano thermite dust everywhere is plenty of evidence in itself. Also U of Alaska Fairbanks recently wrote a paper saying the official story was basically BS
http://ine.uaf.edu/wtc7
"The principal conclusion of our study is that fire did not cause the collapse of WTC 7 on 9/11, contrary to the conclusions of NIST and private engineering firms that studied the collapse. The secondary conclusion of our study is that the collapse of WTC 7 was a global failure involving the near-simultaneous failure of every column in the building."