Ex-F.B.I. Chief Says He Felt Betrayal at Deep Throat's Unmasking

Buried in this article is the following passage:

Mr. Gray said he provided internal F.B.I. investigative files to the White House only after he had been cleared to do so by the bureau's general counsel. He said he had been justified in burning the files because their contents were unrelated to Watergate.

One file contained top-secret cables apparently forged by Mr. Hunt that made it appear the administration of President Kennedy had been implicated in the assassination of President Ngo Dinh Diem of South Vietnam in 1963. A second file contained false letters apparently intended to embarrass Senator Edward M. Kennedy, Democrat of Massachusetts, if he ran for president.

Kennedy's involvement in the assassination of Diem and the subsequent blowback are the subject of The Deaths of the Cold War Kings: The Assassinations of Diem & JFK by Bradley S. O'Leary, Edward Lee

From Publishers Weekly:

In this analysis of the 1963 assassinations of South Vietnamese leader Ngo Dinh Diem and President Kennedy, journalist O'Leary (Presidential Follies) and novelist Lee (The Stickmen, etc.) promise a lot more than they deliver. They claim that a French heroin syndicate, the U.S. Mafia and top South Vietnamese officials--the latter upset over alleged U.S. involvement in the killing of the Diems--conspired to kill Kennedy. The assassin, the authors contend, was a French WWII hero-turned-drug smuggler.