Transcript for Intrigue still surrounds assassination of President John F. Kennedy
And it's great to have you with us here on a Thursday night. And we begin with that headline just a short time ago. Those top secret JFK files. The president tweeting they were coming today. The final batch of classified documents. A short time ago, the white house now explaining why we've seen nothing so far. Teams of historians and reporters waiting all day long to learn more about that fateful day, including what more did the CIA possibly know about Lee Harvey Oswald before the assassination? His trip to Mexico, his visits to the embassies of Russia and Cuba. Tonight, new concern that releasing some of that material could pose a national security threat. ABC's chief national correspondent Tom llamas, leading us off from Washington. Reporter: Tonight, more confusion and drama surrounding the assassination of JFK. President trump announcing some of the secret documents scheduled to be released today will not be, because they pose a danger to national security. 2,800 other documents are being released to shed more light into the killing. And Mrs. Kennedy. Reporter: On November 22nd, 1963, president Kennedy and the first lady arriving in Dallas, on that day that would change America. That tragic trip through dealey plaza, the first couple riding through that windy road in Dallas in a Lincoln continental with the top down. The president an open target for assassin Lee Harvey Oswald. President Kennedy has been shot in Dallas, Texas. Reporter: From the get-go, the news was so hard to believe. A single man with a rifle killing the protected leader of the free world. Then, just days late end on live television -- There is Lee Oswald -- He's been shot! Reporter: -- The man who pulled the trigger, shot and killed himself in the custody of police officers. All of this sparking intrigue and doubt. Assassins need payrolls, schedules, times, orders. This was a military-style ambush from start to finish, a coup d'etat with Lyndon Johnson waiting in the wings. Reporter: The film "JFK," and it's fictional plot surrounding a conspiracy to kill Kennedy, fueling even more speculation, and, in part, leading congress to pass a law to release all federal assassination records by today. Experts say some of those secret documents concern Oswald, and his trip to Mexico City seven weeks before the killing. His visits to the Russian embassy and Cuban consulate there, and possibly what the CIA and FBI knew about his intentions to want to kill the president. And everyone will be mining the documents for any clues to the big question -- did Oswald act alone? I would like to think that these documents would be a final answer, where Americans could look at this case and say, okay, this is what happened. But realistly, that's never going to happen. And the wait continues. Tom llamas, one of those reporters waiting all day. He's live tonight at the national archive. We are expecking some of those times still tonight? Reporter: That's right, David. About 2,800 files will be released tonight. The delay on those other files, it was because president trump felt they were a threat to national security, if they were to be released, but they're going to be re-examined. The most amazing part about today, congress initiated this act so it would call come out in the clear for the public. This is now going to add more fuel to all those conspiracy theori theories. David? Certainly will. Tom llamas tonight, thank you.
This transcript has been automatically generated and may not be 100% accurate.