Several U.S. government agencies were involved in investigating the murder of President Kennedy. There have been persistent allegations that accused assassin Lee Harvey Oswald was himself an agent or asset of US intelligence.
The CIA and the JFK Assassination – The Central Intelligence Agency had a file on Oswald before the assassination, and assisted in foreign conspiracy aspects in the aftermath. But should the Agency have been a suspect in the assassination?
Other organizations were involved in the investigations or the larger story:
FBI – The Federal Bureau of Investigation had primary responsibility for investigating the assassination, interviewing thousands of people. J. Edgar Hoover viewed the Warren Commission as an adversary.
Dallas Police – The Dallas police conducted the initial investigation of the assassination, though was quickly superseded by the FBI.
Secret Service – The Secret Service also conducted an early investigation into the assassination. This agency has primary responsibility for protection of the President.
Department of Defense – Lee Oswald was a former Marine, prior to his defection to the Soviet Union. Many experts believe Oswald’s defection was a cover and that he was an intelligence agent of the military, possibly the Office of Naval Intelligence, or CIA.
Justice Department – The FBI nominally reports to the Justice Department, which was headed by Robert Kennedy under JFK. Assistant Attorney General Nicholas Katzenbach was involved in the formation of the Warren Commission.
State Department – The State Department was involved in handling matters relating to Oswald’s defection and his return to the U.S. It also granted him a passport in the summer of 1963.
Organized Crime – Organized crime figures were hired by the CIA to help carry out plots to assassinate Cuban leader Fidel Castro. Some experts believe that organized crime figures were involved in JFK’s murder.
Cuban Exiles – Many Cuban exiles were extremely unhappy with President Kennedy for his failure to come to the rescue of the disastrous Bay of Pigs invasion of Cuba. Lee Oswald had dealings with certain Cuban exiles in the summer of 1963.
The Kennedy-CIA Divergence Over Cuba, by Peter Dale Scott.
The Secret Service: In Their Own Words, by Vincent Palamara.
Politics and Policies of JFK and RFK: The McClellan Committee Investigation of Organized Labor, by Dr. Anthony Baltakis.
Anatomy of the Ultra-Secret National Security Agency, by Robert David Steele.
Mysteries of the 112 Intelligence Corp Group, by Larry Hancock.
Reports of the Presidents' Foreign Intelligence Advisory Board: An Introductory Overview, John M. Williams, PhD.
Oswald and U.S. Government Agencies. Warren Report, p.659.
HSCA Final Report, Part C. The Committee Believes.....President John F. Kennedy was Probably Assassinated as the Result of a Conspiracy...". p.119. Subsections detail the Committee's findings about various organizations, including the CIA, FBI, Secret Service, Department of Justice, Organized Crime, Cuban exiles, and foreign governments.