Researchers Garland Branch, Eliot Sperling and Natalie Gonzalez, note that federl agencies have defied the JFK Records Act before.
Although the JFK Act explicitly stated that all assassination-related records were not to be “destroyed, altered, or mutilated in any way,” that provision was ignored many times. Agents in the CIA, FBI, and other organizations intentionally destroyed documents. However, we have no idea how many files were destroyed, nor what was in those files. A memorandum found in Oswald’s CIA file states that the Office of Security destroyed most of the files on Oswald in April 1994 from its program, which monitored mail sent to and from Communist Bloc countries, including the USSR, China, and Cuba. And, even before the Act, government officials admitted to destroying records that might have shed light upon JFK’s assassination.