Neither the FBI nor the Warren Commission (WC) overlooked the Oswald's contacts with the Cuban consulate in Los Angeles. They were simply irrelevant.
Oswald was released by the U.S. Marine Corps (USMC) at Air Station El Toro, Southern California, on September 11, 1959. Even if he would have been infatuated with the Castro revolution more than with the Russian language, which he learned at fast pace by that time, Castro wasn't driving him against the U.S. The dispute between Washington and Havana hasn't publicly erupted yet. On September 3-4, 1959, U.S. Ambassador Bonsal talked with Castro about "serious concerns," but also expressed "the general sympathy with objectives of Cuban revolution and similarity with many of our own aims and aspirations."
The FBI interviewed 26 Marines acquainted with Oswald at El Toro in 1959. None of them directly connected Oswald to Cuban officials. Dr. Latell lets slip "if the WC had asked Nelson Delgado," but his testimony is far from useful for making the point of an early Oswald's engagement with the budding Castroit intelligence. On the contrary, the only known witness on the spot, Gerald Patrick Hemming, told Dick Russell in an exclusive interview for the magazine Argosy:
"I ran into Oswald in Los Angeles in 1959, when he showed up at the Cuban Consulate. The coordinator of the 26 th of July Movement [Castro's political group] called me aside and said a Marine officer had showed up, intimating that he was prepared to desert and go to Cuba to become a revolutionary. I met with the Marine and he told me he was a noncommissioned officer (") I thought he was a "penetrator' [and] I told the 26 th of July leadership to get rid of him."
Notwithstanding, Dr. Latell spins the yarn about a DGI file on Oswald "probably" opened when he contacted with Cuban officials in L.A. (1959), "transferred" as the Cuban Consulate closed when the diplomatic relations were severed (1961), and then filled with "evidence of his militancy [and] conspicuous pro-Castro activities in New Orleans" (1963). This ghostly DGI file is an insult to sound JFK studies.
Peter Dale Scott documented in Oswald, Mexico, and Deep Politics (Skyhorse Publishing, 2013) that both CIA and FBI sources reported that "Oswald was unknown to Cuban Government" when he visited the Cuban Consulate in Mexico City on September 27, 1963 (page 33). John Newman demonstrated in Oswald and the CIA(Carroll & Graf Publishers, 1995, 2008) that the CIA, not the DGI, closely and constantly tracked Oswald since his defection to the USSR in Halloween 1959 (page 318). Jim DiEugenio pinned down in Destiny Betrayed (1992, 2012) that in New Orleans, 1963, Oswald was handing out the run-out 1961 edition of the pamphlet The Crimes against Cuba, by Corliss Lamont, from which the CIA had ordered 45 copies when Oswald was living in the USSR (page 219).
In " The Oswald File: Tales of the Routing Slips " (Washington Post, April 2, 1995), Jeff Morley reported how three CIA teams were watching Oswald all the way down from Moscow (1960) to Dallas (1963): the Counterintelligence Special Investigation Group (CI-SIG), the Counterintelligence Operation (CI-OPS), and the Counter-Espionage unit of the Soviet Russia Division (CE-SR/6). The CIA did certainly have a thick file on Oswald and dealt him with three index cards .
The Covert Operations Desk created the first one on May 25, 1960, upon the report by FBI Special Agent John Fain in Dallas after interviewing Oswald's mother and brother about "Funds Transmitted to Residents of Russia." The second one was attached to Oswald's personality file (201-289248) , opened on December 9, 1960. The report by FBI Special Agent Warren De Brueys about Oswald's membership in "the New Orleans chapter of the Fair Play for Cuba Committee [FPCC]" generated the third one for the FPCC file (100-300-011) on October 25, 1963.
For having Castro involved in a conspiracy of silence on Oswald, Dr. Latell must "concoct the dots." A conspiracy of silence inside the Company is completely unraveled by connecting the dots of the October 63 cable traffic between the CIA Station in Mexico City [MEXI] and the CIA Headquarters in Langley [HDQS].
MEXI concealed all intel to HDQS about Oswald visiting the Cuban diplomatic compound on September 27, while HDQS hid from MEXI all intel about Oswald's pro Castro activism in Dallas and New Orleans, including his street scuffle with Cuban exiles on August 9, 1963. HDQS actually lowered Oswald's security profile by quoting --as latest info available on him-- a May 1962 memo from the U.S. Embassy in Moscow: "Twenty months of realities of life in Soviet Union had clearly had a maturing effect on Oswald."
HDQS went further by excluding from another cable --to Department of State, FBI and Navy-- the intel furnished by MEXI about an eventual contact between Oswald and KGB officer Valeriy Kostikov at the Soviet Consulate. To cap it all, HDQS forwarded as Oswald's the description given by MEXI of an American allegedly spotted at the Soviet Embassy on October 1, 1963: "Approximately 35 years old, with an athletic build, about 6 feet tall, with a receding hairline."
The liaison officer of the CIA Counterintelligence (CI) Staff, Jane Roman, signed off on these cables. More than three decades later, Newman asked her if the October 63 cable traffic indicated some sort of operational interest in Oswald's file. Roman flatly answered : "Well, to me, it's indicative of a keen interest in Oswald, held very closely on the need-to-know basis."
The FBI also had opened a file (105-82555) and even issued a FLASH warning on Oswald after the U.S. Embassy in Moscow reported his defection. However, he returned to the States with his wife and their 4-month-old daughter on June 13, 1962, thanks to a $435.71 loan from the Department of State. FBI Special Agent Fain debriefed him in Forth Worth twice and dated the final report on August 30, 1962. Oswald "agreed to contact the FBI if at any time any individual made any contact of any nature under suspicious circumstances with him." No wonder he "was desirous of seeing an agent of the FBI" after being arrested for the scuffle with Cuban exiles in New Orleans. Special Agent John L. Quigley satisfied such a desire of a pro Castro activist.
Like the other town criers of "Castro did it," Dr. Latell overlooks that an ex Marine corp-defector from the USSR is an intelligence bonanza. Neither the CIA nor the FBI could have missed him as security risk after visiting both the Soviet and the Cuban diplomatic venues and eventually contacting KGB and DGI officers. Much less if since September 10, 1963, the FBI in Dallas had reported Oswald as "subscriber to The Worker, an East Coast communist newspaper, [who] was in contact with the [FPCC], passed out pamphlets [and] had a plackard (sic) around his neck reading, "Hands Off Cuba, Viva Fidel'."
Even so, FBI Supervisor Marvin Gheesling canceled the FLASH on October 9, 1963. In view of the JFK visit to Texas, the Secret Service couldn't have then enough intel about Oswald for putting him on the Security Index. Unless there was a conspiracy of silence, not by Castro, but by the CIA and the FBI, Oswald should have never been on the presidential motorcade route in Dallas.