The FBI had a fairly extensive pre-assassination file on Lee Harvey Oswald, but the first reports on Oswald to cross the director's desk originated with military intelligence. Hoover imposed his own interpretation on the army's intelligence reports on Oswald that fitted neatly into his version of assassination history. Two hours later, while on the phone with Assistant Attorney General Schlei, Hoover gave the Justice Department official the benefit of his reading of U.S. history and the political leanings of presidential assassins. It was the director's considered opinion that such killers were always either "anarchists" or "communists." Later in the day the Dallas field office, after prodding from FBIHQ, started compiling biographical material from Oswald's FBI file and interview sessions at Dallas police headquarters with the alleged assailant. An FBI agent lifted some of this material from Oswald's wallet when the suspect left the interrogation room to relieve himself. One of the items receiving special attention was a "Fair Play for Cuba, New Orleans Chapter" membership card issued to L. H. Oswald by chapter president A. J. Hidell, which was assumed to be a fictitious name for Oswald himself. Later that same day FBI HQ had a chance to review the agency's pre assassination file on Oswald. The salient biographical data in the file strengthened Hoover's conviction that Oswald was the assassin: In 1959 Oswald had told U.S. Embassy officials in Moscow that he was a "Marxist" and wished to renounce his American citizenship. In exchange for Soviet citizenship, he offered to tell the Soviets what he knew about the U.S. Marine Corps and his specialty as a radar operator. The ex-marine had distributed pro-Castro "Fair Play for Cuba" literature in New Orleans and, according to a "confidential informant," Oswald subscribed to The Worker, the East Coast organ of the American Communist Party. ''

Before the day was over the biographical details about Oswald were fitted to Hoover's profile of a presidential assassin. That same day, the word went out from FBI HQ to the Dallas field office that Oswald was not just the principal suspect; he was the only suspect. A Richardson, Texas, law officer called the FBI Dallas office the afternoon of the assassination with the name of a possible suspect, Jimmy George Robinson, and other members of the white supremacist National States Rights Party because of their open hatred for President Kennedy. Before the office memo recording the call was serialized and filed-and it was filed the day of the assassination-it carried the handwritten notation: "Not necessary to cover as true suspect located." In short, within a few hours of the assassination, the FBI was not interested in any possible conspiracy or any suspect other than Lee Harvey Oswald. No action was taken on the lead from Richardson, although the call came in before the Dallas authorities charged Oswald with killing President Kennedy. He was not charged with JFK's murder until 11:25 p.m.

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."