WASHINGTON (AP) — President Donald Trump is playing it coy on what people will see from long-secret JFK assassination-era files.

He’s been caught between students of the killing who want every scrap of information out on that crucible of history and intelligence agencies that are said to be counseling restraint. How that plays out should be known Thursday, the day set in law 25 years ago for the disclosure of remaining hidden documents on Kennedy’s killing on Nov. 22, 1963. Only the president can hold some back.

Trump wasn’t tipping his hand on the eve of the release. “The long anticipated release of the #JFKFiles will take place tomorrow,” was all he said in a tweet. “So interesting!”

Scholars and sleuths say the CIA is pushing Trump to keep some of the materials secret. The spy agency isn’t denying that.

“Clearly there are documents, plural, files, plural, being appealed to him,” said University of Virginia historian Larry Sabato, an authority on Kennedy. Of the pressure on Trump, Sabato said, “I’m told reliably that it continues and that it has intensified.” The historian said documents generated in the 1990s that could contain the names of people who are still alive are of particular concern to those who want files held back.

Whatever details are released, they’re not expected to answer the major — and for many, still-lingering — question of whether anyone other than Lee Harvey Oswald was involved in the assassination, including the government. The Warren Commission in 1964 reported that Oswald had been the lone gunman, and another congressional probe in 1979 found no evidence to support the theory that the CIA had been involved. But other interpretations, some more creative than others, have persisted.

For example, Roger Stone, a close Trump ally, advanced the unsubstantiated and widely disdained theory that Lyndon Johnson, who became president upon Kennedy’s death, was involved in it.

Stone is not sure key documents will see the light of day. He said that 440 documents related to the assassination, released by the National Archives in July, were so heavily redacted “on the basis of ‘national security’ that they are useless.” Stone said he’s lobbied Trump personally to release all remaining materials and believes the CIA is pushing the president to keep some secret.

In 1992, Congress passed the President John F. Kennedy Assassination Records Collection Act, which directed the National Archives to collect all information related to the assassination and release it within 25 years, barring exceptions designated by the president. The deadline is Thursday.

The gunshots that the Warren Commission said killed Kennedy almost immediately inspired theories about whether Oswald had been the lone gunman who, with extraordinary luck by any measure, had hit his target.

As the nation mourned in disbelief, Oswald was shot and killed in police custody by Jack Ruby — forcing Americans to consider whether their government was hiding what it knew of the assassination. The event remains in the nation’s living memory for a significant slice of the country. Forty-nine million Americans, or 15 percent of the country, are age 65 and over, according to the Census Bureau. They were around age 11 or older at the time.

The Warren Commission did little to settle the matter. Theories abounded that Oswald’s murder was a cover-up for a conspiracy or government ineptitude. The deadly aim of a lonely, alienated gunman seemed hard to fathom.