“It’s kind of like discovering a dusty box of papers in your parent’s home,” NBC’s Peter Alexander remarks this morning … if your dad was J. Edgar Hoover or James Jesus Angleton. Mostly as promised, the government finally released most of its heretofore secret archive on the assassination of President John F. Kennedy almost exactly fifty-four years ago. After a last-minute objection from the CIA, a small group of documents were withheld for further review, but there’s enough to keep historians busy for a while — including an unknown statement from FBI Director Hoover two days after the assassination.

In a memo dictated to the Warren Commission after the murder of Lee Harvey Oswald by Jack Ruby, Hoover expressed concern that the American public would not believe that Oswald carried out the assassination on his own. He told then-deputy AG Nicholas Katzenbach that the commission needed incontrovertible proof. Was that an observation, or something more imperative?

Scholars and other experts have repeatedly said it’s unlikely that there’s anything groundbreaking in the documents. But as journalists and historians pored through the enormous database of material Thursday night and Friday morning, some interesting nuggets were turning up, among them Hoover’s Nov. 24 memo.

Hoover appeared to be particularly concerned that the public would have to be compelled to believe that Oswald was a lone actor — not part of a larger conspiracy.

In the 1964 Warren Report on Kennedy’s assassination, Hoover was firm in stating that he hadn’t seen “any scintilla of evidence” suggesting a conspiracy — a sentiment he expressed in other public forums, as well, but not in words as blunt as those he used the day Oswald was killed.

Referring to Nicholas Katzenbach, the deputy attorney general at the time, Hoover dictated: “The thing I am concerned about, and so is Mr. Katzenbach, is having something issued so we can convince the public that Oswald is the real assassin.”

If nothing else, Hoover turned out to be prescient. It didn’t take long for the Warren Commission’s conclusions to come under fire, and an entire JFK-conspiracy industry to emerge. Katzenbach’s thoughts at the time are already well known, as his own memo from the next day had been released long ago:

Katzenbach is known from previously released documents to have shared Hoover’s concern, writing in a memo the next day, on Nov. 25, 1963, that “the public must be satisfied that Oswald was the assassin; that he did not have confederates who are still at large; and that evidence was such that he would have been convicted at trial.”

The NBC report questions whether Hoover really thought there was a conspiracy and wanted it covered up, or whether he was concerned about conspiracy theorists muddying up a straightforward case. Given the short time between the memos and the assassination, it’s almost certainly the latter. If there had been a conspiracy large and ominous enough to cover up, it would have taken more than two days for Hoover to have known about it (three days for Katzenbach).

That becomes more obvious when Hoover vents his ire at the Dallas Police Department for allowing Oswald to get murdered in their custody. Hoover isn’t worried about losing a witness; he’s worried about the “civil rights people” that will protest because “he was handcuffed and had no weapon. There are bound to be some elements of our society who will holler their heads off that his civil rights were violated,” Hoover continued, and added, “which they were.” If Hoover was concerned about a conspiracy, his anger wouldn’t have been over Oswald’s civil rights being violated.

CBS News has been live-blogging the revelations since last night and found a few more nuggets. Among them is a document from a month before the assassination that describes Oswald’s contacts “with Cuban sources,” but appears to be mainly pro-Cuban agitators:

FBI memo discusses Oswald prior to JFK assassination:A document originating with the New Orleans office of the FBI appears to discuss Lee Harvey Oswald before he killed President Kennedy. The document, marked “10/25/63,” indicates that an FBI agent or agent was keeping up “with Cuban sources” for information relating to the Pro-Castro “Fair Play for Cuba Committee,” which Oswald was a member of.

The document says that the committee appears to have gone dormant since Oswald left the area, and that the “Dallas Division for information” is searching for Oswald. It says that if Oswald has relocated to Dallas “he may inaugurate an FPCC branch in that area.”

Another document unearthed details information from a supposed KGB defector in 1966 who claimed that the Soviets were “shocked” at Kennedy’s assassination. They preferred JFK to Lyndon Johnson, the defector claimed, because Kennedy was more predictable. As for Oswald, he was considered “a neurotic maniac” whom they were happy to be rid of, as he was “disloyal to his country, and everything else.”

And just because it wouldn’t be a JFK file without it, CBS also found an FBI document on Kennedy “sex parties” with his Hollywood pals before his election as president. It’s not as groovy as you’d think, though:

1960 document discusses “sex parties”: One new FBI document discusses a “high-priced Hollywood call girl” and friend of Los Angeles private detective Fred Otash, who had “convicted of horse race fixing.” The woman in question contacted members of the FBI’s Los Angeles field office to tell them that Otash had asked about her “participation in sex parties” that included then-Senator John Kennedy, his brother-in-law Peter Lawford, Frank Sinatra, and Sammy Davis Jr. She also told agents that she knew of no such sex parties.

Otash later implied to the FBI that “Confidential” magazine was “looking for dirt on Kennedy or Lawford” that it could use before the 1960 election.

Guess they didn’t find any.