- Recipe for a Coverup Conspiracy theorists often point to a memorandum written by Assistant Attorney General Nicholas Katzenbach three days after the assassination as a call for a top-level government coverup of a conspiracy. One passage from the memo reads: The public must be satisfied that Oswald was the assassin; that he did not have confederates who are still at large; and that the evidence ...mcadams.posc.mu.edu/context2.htm