Rebekah Roth has written several books on events of 9/11
She was an airline stewardess and got clues of what occurred
from what was said from the airplanes on 9/11
She has done a ton of research and lectures regularly
Lots of video lectures on her
Here is one from 2015
https://www.youtube.com/watch?v=Iq1sgoYrfAA