Under Hoover's direction the FBI's handling of Oswald's Mexico City activities was simply a repetition of the way the director and bureau elites dealt with the larger, controlling issue of the assassination itself. That is to say, the politically determined theory of the crime-Oswald acting alone took the president's life-took iron-clad, unamendable precedence over all the evidence and witness testimony. President Johnson and Hoover had agreed on the "official truth" of Dallas over the weekend following the assassination. When LBJ, anxious to "settle the dust" of Dallas, asked that the FBI report on the assassination be on his desk by Tuesday, November 26, the day after Kennedy was buried, Hoover notified the General Investigative Division "to wrap up investigation; seems to me we have the basic facts now:"" Only two developments delayed for the moment this rush to judgment: The first was Hoover's suspicion regarding Oswald's assassin, Jack Ruby, and his easy access to Oswald in the basement of the Dallas police department. The second unanticipated development was the revelation from Mexico City about an Oswald imposter and a possible KGB-Castro conspiracy to assassinate Kennedy.
As soon as FBI Washington had proved that the Alvarado story was bogus and conspired with the CIA to suppress from the Commission any revelations about an Oswald imposter, Hoover closed the book on any further FBI investigation into the "potential Cuban aspects" surrounding Oswald and his seven days in Mexico City. It would have been expected that the FBI's General Investigative Division (GID) would carry the major responsibility in any legitimate investigation into the Kennedy assassination. Up to a point, this was true. The FBI report that LBJ wanted on his desk by November 26 was prepared by the GID. According to Assistant Director Alex Rosen, the head of that division, the "basic investigation was substantially completed by November 26, 1963," to meet the White House's expectations." After the GID turned in its thrown-together report the division was relegated to the margins of the investigation. Rosen himself was assigned to the bureau's bank-robbery desk. The GID head would later characterize the FBI's investigative efforts into the Kennedy assassination as "standing around with pockets open waiting for evidence to drop in." Even more telltale was Hoover's order on November 23 to cancel all bureau contacts with Cuban sources. He followed this up by excluding the FBI's Cuban experts and supervisors in the bureau's own Cuba Section of the Domestic Intelligence Division from any investigation into Oswald's Mexico City activities. The director focused the probe away from Mexico and the Caribbean to the Soviet Union. Investigation into Oswald's political activities and associations was turned over to the bureau's Soviet experts.
In concert with the FBI, CIA Langley pulled the plug on an honest investigation into any Cuban aspects of the Kennedy assassination. In the CIA's case, the process was more indirect and devious, but the end result was same. Initially, the CIA's deputy director of plans, Richard Helms, appointed John Whitten to undertake the agency's in-house investigation into the assassination. Whitten was a senior career officer with twenty-three years in the clandestine service. In 1963 he was the head of WH-3, the agency's designation for the Western Hemisphere Branch that comprised Mexico and the Caribbean. The WH-3 head had a staff of thirty officers and about an equal number of clerical staff. What Whitten did not suspect at the time was that Helms and the chief of the CIA's Counterintelligence Branch, James Jesus Angleton, had set him up for failure. There is good reason to believe that Hoover was part of an interagency scheme to thwart any good faith investigation into the suspicious machinations surrounding the activities of the CIA's Mexico City station.
Theoretically, Whitten had the experienced area professionals, staff, and informers to conduct a sweeping investigation into Oswald's activities in Mexico City, but during the short time that Whitten was in charge of the investigation he ran into a stone wall. The FBI deluged his branch with thousands of reports containing bits and fragments of witness testimony that required laborious and time-consuming name checks. Whitten characterized most of the FBI information as "weirdo stuff." None of this mountain of paper contained vital information that was critical to any legitimate probe into the assassination. For example, Whitten knew nothing of Oswald's alleged pro-Castro activities in New Orleans during the summer of 1963, Oswald's so-called Historic Diary with insights into his years in the Soviet Union, or the FBI's assertion that JFK's charged assailant had attempted to take the life of General Edwin Walker. Whitten knew none of this until, at Katzenbach's December 6 invitation, he was allowed to read CD 1. By that time Helms and Angleton were preparing to pull the investigation out from under him.
In the chain of command for WH-3, COS Win Scott was under Whitten and, in the bureaucratic scheme of things, expected to report directly to Whitten. But Scott, Whitten's subordinate, never told him about Oswald's contacts with the Cuban and Soviet embassies until the day Kennedy was assassinated. Equally remarkable was the fact that Whitten had never heard of Lee Harvey Oswald until November 22, 1963, even though the CIA had a restricted 201 pre assassination file on Oswald held by the Counterintelligence/Special Investigative Group, indicating that this branch of the CIA confined to sensitive counterintelligence operations may have had a special interest in former marine PFC Lee Harvey Oswald."