Actually, the new material, aired either Sunday or Monday night, involved Oswald's Mistress, a Cancer researcher, who, along with a Cancer Institute were developing, and testing [on prisoners from Louisiana's Angola Prison] a souped up Cancer causing agent.
When coupled with X-Rays to suppress the target's Immune System, they got sick and died quickly.
Oswald's trip to Mexico City involved, in part, the delivery of the final agent to a Cuban doctor who was to administer it to Castro. That part was unsuccessful.
The last part squarely implicates LBJ, who Bobby Kennedy, as Attorney General, was preparing to Indict over corruption [and MURDER] in Texas.
Billie Sol Estes named LBJ [several years after LBJ's death] as having been involved in the planning of EIGHT separate Murders, the eigth being that of President John Fitzgerald Kennedy.
Seems the Castro thing got bumped to a lower priority than the Kennedy takeouts [both] in the Autumn of 1963, as Bobby moved in to nail LBJ!!
The Cancer causing agent may have been used on Jack Ruby, who came down with a fatal, agressive and inoperable Stomach Cancer in a little more than two years after his conviction in the Oswald murder case.
And, by the way, Jack Ruby knew Lee Harvey Oswald.