Here is John Newman doing a presentation on C-Span in September 2014.
About 9 minutes into it, he said the following:
"Whether Oswald was there in Mexico City or it was somebody else matters less than tying the Oswald name to the Cubans and the Soviet Union. Let's not forget that. In my presentation today, I will place the Cabella operation to kill Castro into the adjacent area of the same puzzle. The operation to kill the President was in play underneath both the Oswald Op in Mexico City and the Cabella Op to assassinate Castro."
My point in quoting that is to show that, as late as 2014, just two years ago, John Newman recognized the possibility at least, that it wasn't the real Oswald of fame who went to Mexico City. He recognized that the whole thing (Oswald going to Mexico City) was a CIA operation, from start to finish. And, he likened it to the operation of having Oswald hand out leaflets for the Fair Play for Cuba Committee in New Orleans and filming it. They were both CIA operations, he said.
So, Oswald in front of the Trade Mart leafletting for the FPCC was a CIA operation all the way, and Oswald in Mexico City visiting Russian and Cuban embassies was a CIA operation all the way. That's what John Newman said.
But, there was a gigantic difference. In the New Orleans operation, there are images of the real Oswald of fame doing it.
But, there are no images of the real Oswald of fame in Mexico City; rather, there are only images of Oswald impostors.
This makes it extremely likely that John Newman was right in suggesting that the real Oswald of fame may NOT have gone to Mexico City.
I am going to try to contact John Newman about this. Here is the link to his presentation on C-Span: