What is wrong with the NIST report?

I would like to know why i can find FBI reports on other aviation crashes but i can not find any FBI reports on any of the 911 crashes.

911commission.gov...

By law, the FBI becomes the lead investigative agency when airline crashes are the result of a criminal act, and the NTSB provides support when requested. [37] However, the families were advised by FBI officials that the FBI is investigating only the terrorists. Why, then, have we heard nothing from the NTSB?

According to Mary Schiavo, former Inspector General of the Department of
Transportation, "In every single aviation disaster, whether there was criminal activity or not, in every single one in the course of aviation history it has been followed -- not only where necessary a national criminal investigation -- but also a National Transportation Safety [Board] investigation into what went wrong in the aviation system so that it never happens again." [38]
NTSB experts would examine flight and data recorders, and ATC radar tracking data, as well as evaluate the transcripts of air controller-pilot conversations and study air traffic control service on September 11th. They would have also collected airframe wreckage at the scenes and interviewed eye witnesses. Finally, the NTSB would have assessed survival factors, based on documentation of impact forces, emergency planning and crash-fire-rescue efforts, [39] all of which would have contributed to a better understanding of what happened that morning.