The Final JFK Assassination Documents Are About to Drop. Here’s What to Know

Thursday is a date that, for 25 years, has loomed large on the calendars of the curious: Oct. 26, 2017, the final deadline for the release of all government records pertaining to the assassination of President John F. Kennedy in 1963. Though JFK enthusiasts had worried the final release might never come or would be further delayed, as the President does have the authority to intervene, the release appears to be on track.

Since 2014, a National Archives and Records Administration team has been working to prep the remaining documents for release by that deadline. In July, the first batch of previously withheld documents covered by the law was released online, comprising more than 400 documents that had been fully withheld and nearly 3,400 that had previously been redacted in part.

Earlier this month, resolutions were introduced in the Senate and House urging President Trump not to intervene in the release of, by their count, about 3,000 more unreleased documents and over 30,000 that had been redacted when previously released. As of March, no agency had notified the National Archives (NARA) that they were trying to keep their documents from being released. Last week, with the deadline just days away, NARA told TIME that while it could not disclose whether any agency appeals to further postpone release had been made, the National Archives continued to prepare for a release by the deadline. “CIA continues to engage in the process to determine the appropriate next steps with respect to any previously-unreleased CIA information,” Nicole de Haay, a CIA spokesperson, told TIME. And, on Saturday, President Trump tweeted that, barring a last-minute change, he would allow the files to be opened.

The deadline is the result of a law that was passed in 1992, which declared that those records should be disclosed “to enable the public to become fully informed about the history surrounding the assassination.” Finding that public curiosity continued though the need for secrecy had passed, Congress created the JFK Assassination Records Collection at the National Archives as well as the Assassination Records Review Board, which determined whether a document was covered by the law and, if so, whether there was any reason to postpone that document’s release.

In the late 1990s, after the board concluded its review, 88% of all the documents had been released to the public. Even so, there was a deadline for the rest, the act explained:

But, as those fascinated by Kennedy history gear up for Thursday, what exactly might be found in the final release? And why might any government agency be worried about the information contained in half-century-old documents?

As Martha Murphy of the National Archives told TIME last year, anyone hoping for a new twist to add to assassination conspiracy theories may be disappointed, as the bulk of the collection is already public and most of the information due to be disclosed at the end was classified as “not believed relevant” to the assassination when the Review Board initially met in the 1990s. And, as she and NARA’s James Mathis explained in a fall 2017 article, anything that was relevant would fall under the JFK Act’s strict rules governing release, and has likely been public for decades now. The exception would be documentation that an agency was able to demonstrate required protection, in which case a redacted version was likely released before.

Judge John R. Tunheim, who chaired the Assassination Records Review Board, says it’s hard to give advice about what the curious might look out for in the final release, as the records fall into so many different categories. (A few categories that specifically won’t be released include some grand jury information and personal tax records.)

“They really run the gamut, across the federal government of that time, when we were classifying virtually all of that material,” he says, though he, like Murphy, doubts that any of the information released this week will substantially change the general public’s view of the assassination. “We were very specific about releasing anything that was directly related to the assassination, regardless of whether an agency opposed its release or not. What we were protecting was ancillary information.”

That doesn’t mean the ancillary information won’t be interesting, though. For example, Tunheim recalls that there was a batch of records “largely associated with the intelligence-gathering mechanisms that we’d worked out with the country of Mexico in the early 1960s” that received a postponed release because it was thought that the evidence of such close collaboration between the neighboring nations might be controversial enough to sway the balance of political power in Mexico. Though he has not been personally involved in any of the more recent decision-making about document releases, he says that he sees no reason why that information would affect the U.S. relationship with Mexico “such as it is right now” and would expect that anything that remained withheld might be released now.

Another withheld detail that he recalls is the photographic evidence that the FBI collected while investigating conspiracy theorist Mark Lane; though a description of the evidence was released, the review board honored Lane’s request to keep a sexual photograph from his personal life private. Tunheim says he’s curious to see whether the photos are released now that Lane is no longer living — not because of what the image shows but because it’s “an important side note to the story” to see how personal information was collected about the people who questioned the consensus on the assassination.

In general, such “ancillary” information could help people today better understand Cold War foreign relations. When the board’s term ended in September of 1998, having already been extended past its original cut-off, hundreds of documents had still not been thoroughly processed. As Tunheim recalls, in retrospect more time would have been useful but the staff felt that they’d essentially promised Congress they wouldn’t need another extension and that it was time to wrap it up.

So he’s not closing the door on the possibility of something that is directly related to the assassination popping up all these years later.

“It’s always possible that a really good researcher will find new information that they think is significant and will add to their version of the story, or perhaps even lead them in other directions,” Tunheim says. “There’s a lot of still unanswered questions about the assassination. For example, did Oswald, when he lived in Minsk, have any connection with Cuban intelligence agents who were being trained in Minsk by the Soviets? There are issues like that that aren’t fully resolved anywhere, and going through these documents might give good researchers an opportunity to come up with more than what we know today in the official story.”

Whether the hope expressed by President George H.W. Bush upon signing the 1992 JFK Act is borne out remains to be seen.

“[The bill] will help put to rest the doubts and suspicions about the assassination of President Kennedy,” he said. “I sign the bill in the hope that it will assist in healing the wounds inflicted on our Nation almost 3 decades ago.”