Walton,
If by the "one little episode in Mexico City" you mean the volunteering, to an Oswald impersonator over a sure-to-be-tapped-by-CIA phoneline, the made-radioactive-by-KGB name "Kostikov" by KGB triple-agent Ivan Obyedkov, then you evidently don't understand John Newman's concept of a "World War III Virus" in Oswald's CIA file, and how it was used by evil, evil, evil James Jesus Angleton to force a FBI and Warren Commission coverup of his traitorous actions in masterminding the assassination of JFK.
Or were you referring to short, blond, very thin-faced KGB colonel Nikolai Leonov's providing the Mexico City Cuban Consulate with a passport-sized photo of Oswald that was taken in the USSR?
Or perhaps you were referring to Leonov's claim in 1993 that he had met one-on-one with an emotional, revolver-brandishing Oswald at the Soviet Embassy (not Consulate) on Sunday, September 29, 1963?
Could you please be a little more specific?
-- MWT 
Actually, Tommy, you are misunderstanding the implication of Dr. Newman’s WW3 virus theory; a theory to-which (with immense respect to Dr. Newman) I do not ascribe.
Newman’s WW3 Virus theory says that, rather than flying under the radar, undetected, there was evidence in Oswald’s 201 file that there was an obvious, “Keene interest” (Jane Roman’s words) before his activities in Mexico City, going back to CIA responses to inquiries 6 weeks prior to the Assassination. This information, popping-up after the assassination, was the virus. It showed that that the CIA was handling Oswald at the time.
In my view, and where I depart from Dr. Newman, is that this was meant to force Angleton into moving-forward with the cover-up, protecting the CIA. This is all that was necessary to control Angleton. Angleton did not know of the plot.
The plotters thought that the “evidence” for Oswald’s collusion with Castro, or acting in support if him, would force an invasion.
As it turned-out, there was little desire, among the powerful stake-holders (Texas oilmen and industrialists) to “free” a bunch of Catholic, Spanish speaking, historically mob-affiliated Caribbean islanders, who would compete with American trade and tourism interests; Vegas would do, and be more controllable.
Of course, if things got out of control, and a real distraction from a domestic coup de ta was necessary, that same MC “evidence” could be used to foment a war, stifle a real investigation and garner the patriotic support of the masses through the Mockingbird network.
Angleton, by design, was cought off-guard, his back placed against a wall, and made silent, when Oswald was arrested for the JFKA.
.... edited to reflect the following quote from “What Jane Roman said”.
https://www.history-matters.com/essays/frameup/WhatJaneRomanSaid/WhatJaneRomanSaid_3.htm“Roman understood his point and finally conceded it: “Yeah, I mean I’m signing off on something that I know isn’t true.”
I’m signing off on something that I know isn’t true.
This was doubly interesting. Roman was not only acknowledging not only was somebody in SAS interested in Oswald six weeks before Kennedy was killed. She was stating that whoever that somebody was made an affirmative decision to withhold information about him from other CIA officers before November 22, 1963.
Newman did not dwell on the point. He did not imply that Roman was involved in anything sinister. She was merely saying that she participated in drafting a cable in which the men higher up in the clandestine operations division chose not to tell the whole truth—something that was in the nature of their jobs.
Responsibility for the cable on Oswald, Roman said, belonged to the most senior officer who signed it, Tom Karamessines.
.................
Newman wanted to know how Roman, with the benefit of hindsight, interpreted the contents of the cable about Lee Harvey Oswald that Tom Karamessines’ signed and sent to Mexico City late on the night of October 10, 1963.
“What does this tell you about this file, that somebody would write something they knew wasn’t true?” he asked.
“And I’m not saying that it has to be considered sinister, don’t misunderstand me,” Newman added. “It is one thing if I don’t say anything, I tell you ‘You don’t have a need to know.’ But if I tell you something that I know isn’t true, that’s an action [that] I’m taking for some reason. … I guess what I’m trying to push you to address square on here is, is this indicative of some sort of operational interest in Oswald’s file?”
This was the key question of the interview and Roman took it head on.
“Yes,” she replied. “To me its indicative of a keen interest in Oswald held very closely on the need to know basis.”
