For the record, I do not believe that our government is responsible for executing the events of 9/11/01 — nor do I believe that our government is not responsible for executing the events of 9/11/01. This is not a case of belief. This is a crime that should be solved by a forensic study of the evidence. Before it can be determined who did it, it must first be determined what was done and how it was done.
The order of crime solving is to determine

1) WHAT happened, then
2) HOW it happened (e.g., by what weapon), then
3) WHO did it. And only then can we address
4) WHY they did it (i.e. motive).

Let us remember what is required to convict someone of a crime. You cannot convict someone of a crime based on belief. You cannot convict someone of a crime if you don't even know what crime to charge them with. If you accuse someone of murder using a gun, you'd better be sure the body has a bullet hole in it.