The Church Committee is the common term referring to the United States Senate Select Committee to Study Governmental Operations with Respect to Intelligence Activities, a U.S. Senate committee chaired by Senator Frank Church in 1975.
The FBI HQ main file on the Church Committee is HQ 62-116395. The FBI told me that this HQ file totals more than 50,000 pages.
The Church Committee investigated intelligence gathering for illegality by the Central Intelligence Agency (CIA), National Security Agency (NSA) and Federal Bureau of Investigation (FBI) after certain activities had been revealed by the Watergate affair.
Together, the Church Committee's reports have been said to constitute the most extensive review of intelligence activities ever made available to the public.
Many of the original Church Committee file documents were classified, but more than 50,000 pages have since been declassified under the President John F. Kennedy Assassination Records Collection Act of 1992.
The Church Committee published fourteen reports on the formation of U.S. intelligence agencies, their operations, and their abuses of law and of power that they had committed, together with recommendations for reform, some of which were put in place (see links below).
Among the matters investigated were attempts to assassinate foreign leaders, including Patrice Lumumba of the Democratic Republic of the Congo, Rafael Trujillo of the Dominican Republic, the Diem brothers of Vietnam, Gen. René Schneider of Chile and Director of Central Intelligence Allen Welsh Dulles's plan, approved by the President Dwight D. Eisenhower, to use the Mafia to kill Fidel Castro of Cuba.
About six years ago, I obtained FBI Inspection Reports about the Bureau's Domestic Intelligence Division (aka Division 5). Some of those Inspection Reports were significantly redacted. However, as a result of Church Committee file documents that have now been released as a result of the JFK Assassination Records Act, new less-redacted copies of some of those Inspection Reports are now available in the FBI's Church Committee file.
The file I am uploading into my Internet Archive webpage (623 pages) consists of two Division 5 Inspection Reports from January 8 to January 26, 1971 and then August 17 to September 9, 1971.
Among the subjects discussed in these less-redacted versions are the Huston Plan and various FBI COINTELPRO Programs against the Ku Klan Klan and other white hate groups along with the Communist Party USA.
Also much statistical information concerning the number of FBI informants within legitimate and subversive organizations is no longer redacted.
Also see separate upload which pertains to the October 1963 FBI report entitled "Communism and the Negro Movement: A Current Analysis". The 338 pages I am uploading today concerns the distribution of that FBI Report.
BOTH of these newly uploaded files are quite large so it probably will take another 2 or 3 hours for them to be available on my Archive webpage.