Some one had to. How else would anyone have even heard about it?
Well, a hobbyist could have been reading tail-numbers. However, that would require that bubba-the-reporter know the names of the passengers inside the aircraft. Such specificity defies logic.
An insider leaked, IMHO.
IIRC A local reporter saw it happen and reported on it.
A local podunk reporter got wind of it and got the scoop. If he hadn’t been paying attention we would be clueless about the nefarious meeting.