15 of the 19 were from S.A., and the recently declassified section of the 911 report did imply there was some possible Saudi collusion. I have no idea about the origins of the other 4.
14 of the 19 … none of them the leaders or pilots. Atta the leader of them all was Egyptian with Syrian connections. His Hamburg cell was under the wing of two Syrians, on an Imam played their spiritual advisor ...the other was a Syrian businessman and “former” Syrian intelligence official.
Of the 19 at least one was from the UAE, another from Jordan or Lebanon...forget the others.