The FBI took the leading role in the investigation and relied on technical assistance from the NTSB. You shouldn't resort to lying to further your halluncination, that's just bad form.
Your declaration is false. The FBI has produced next to nothing, going so far as to refuse to release any information confirming what planes were involved in 9/11:
http://rinf.com/alt-news/911-truth/fbi-refuses-to-confirm-identity-of-911-planes/1875/
So, to start with, the FBI has never confirmed what jetliners crashed on 9/11.
It is to be recalled the FBI is said to have returned aircraft debris from Flight 93 to United who then destroyed such debris as they are said to have received from the FBI.
As investigatory process goes, those facts are enough to create a "reasonable doubt" in acriminal trial because essential evidence to prove what happened was either not turned over or destroyed via a process that violates the most basic norms of criminal investigation. Something the FBI is supposed to be good at.
But let us not be coy here. The FBI is, in fact, not stupid. That which was presented as the FBI's denial of a FOIA request and their handling of the Flight 93 debris makes sense only as a 'cover-story' designed to further the deception that jetliners were involved with 9/11 when no such thing happened.
In addition, as to what the NTSB did and did not do, your paraphrase is inaccurate, to put it no more harshly than that.
The NTSB distanced itself from the 9/11 charade in no uncertain terms, stating as follows:
"The terrorist attacks of September 11, 2001 are under the jurisdiction of the Federal Bureau of Investigation. The Safety Board provided requested technical assistance to the FBI, and any material generated by the NTSB is under the control of the FBI. The Safety Board does not plan to issue a report or open a public docket."
The NTSB issued 4 identically worded statements for the events of 9/11 making it clear that it did not reach any determination of what happened.
While that statement is undoubtedly crafted so as to avoid making it clear the NTSB had nothing whatever to do with any "investigation" of 9/11 and was certainly not condoning or backing any findings and conclusions about it, the statement is not likely to get the attention of those who want to believe the common storyline of 9/11.
Put simply, the NTSB said we don't know, the FBI knows. And, the FBI won't say.
Come on posters, this should be enough to cause concern for even the most die-hard adherents to the common storyline.