https://www.americanheritage.com/did-castro-okay-kennedy-assassinationThe above is an interesting article by Gy Russo.
Within the article Russo says this:
"When he (Russo's source, "Oscar Marino," a purported former G-2) was asked when the Cuban secret service first made contact with Oswald, Oscar flinched and gave a long pause, gazing out a window at the tops of some mimosa trees. “It was in the fall of 1962,” he finally said with certainty. He had seen Oswald's name on a foreign collaborators list. He had also been present during high-level discussions on how to make contact with Oswald.
According to the KGB document, a Cuban operative met Oswald “repeatedly, several times,” with the first rendezvous at the end of 1962—exactly when Oscar Marino said it had been."
What KGB document?
I have been trying to locate a contact for Russo.
There is an earlier reference in the above article to a KGB file that chronicled LHO's doings in Minsk.