[Wikipedia, huh? Not sure who wrote this but it doesn’t track what I’ve heard.]
There are several groups of people who *know* what happened. First, the people who killed him, and the people who ordered the killing. Second, the people who were told, after the fact, about the killing. (This *may* include the president and various people who report to him). Third, possibly intel agencies that intercepted elint or obtained humint re the assassination. Everyone else is just guessing, including various authors and commentators who may have written a book or two.
Guess that includes you, doesn’t it?
By the HARP #2 is sitting, lightly rusted at Yuma Proving Ground, all 120 feet of it.
I joked to my fellow experimenters that “all it would take is one Marine and some WD-40 and we’d have that puppy ready to go again”.