At first, he wasn’t even going to bring his camera.

On Nov. 22, 1963, the day Abraham Zapruder would forever surrender his name to an American tragedy, the Dallas dressmaker who loved to shoot home movies had decided to leave his Bell and Howell Zoomatic at home. It was his assistant who convinced him that President John F. Kennedy’s motorcade through Dealey Plaza might be worth getting on film.

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Four hundred and eighty six frames later, Zapruder had not only captured history, he had made it. The 26-second Zapruder film of  Kennedy’s assassination marked the pre-dawn of the viral video age — ordinary citizens with cameras documenting extraordinary events. His 8-mm images initially helped guide Warren Commission investigators to their conclusion that Lee Harvey Oswald acted alone. Later, parsed and scrutinized to this day, the Zapruder film cast doubt on the official explanation and spawned a swirl of conspiracy that would define not just the event but the modern era.

“Without the film, I don’t think there ever would have been a controversy over the Warren Commission or anything like what has gone on for the last 50 years,” said Josiah “Tink” Thompson, author of “Six Seconds in Dallas,” a seminal assassination analysis.

When the reluctant Zapruder finally climbed up on a concrete pedestal, 65 feet from Elm Street, he gave himself a nearly perfect vantage point on destiny.

“It is exactly where a Hollywood director would have set up,” Thompson said.  “At the limo’s closest approach to his camera, Kennedy’s head explodes.”

On Thursday, President Trump released 2,800 secret assassination files from the final batch held by the National Archives. But he also withheld thousands of pages of the most sensitive documents for at least another six months, after intense lobbying by the CIA, FBI and other agencies.

His decision disappointed historians and conspiracy theorists alike. Even so, legions of people began digging through the documents for clues to what really happened in Dallas.

For many, memories of that devastating day quickly revert to that silent, flickering sequence captured by Zapruder. It is as chilling as it is familiar: the approaching convertible, the waves of a crowd about to lose its innocence, the president clutching his throat, the crimson bloom in frame 313 (which wasn’t shown publicly for 12 years), Jacqueline Kennedy’s primal scramble over the trunk, the rush of the motorcade off to a hospital and an America forever changed.

“He really did a remarkable job,” Thompson said of the amateur filmmaker.

It was an achievement that Zapruder would have gladly avoided. The 58-year-old owner of Jennifer Juniors, who came from Russia as a teenager, loved the Kennedys. He climbed down from his perch, put the camera down and screamed “They killed him! They killed him!”

“I think he was very sorry to be the guy who got it on film,” said Alexandra Zapruder, the filmmaker’s granddaughter, who last year wrote “Twenty-Six Seconds,” a personal history of the film’s effect on her family. “It brought him nothing but heartbreak.”

In the chaos after the shooting, according to an exhaustive timeline compiled by the assassination website JFK Lancer, a Secret Service agent rushed Zapruder to a Kodak lab where the film was processed on the spot. Zapruder provided two copies to the government, and kept the original and one copy himself. Within three days, he’d sold the original and all rights to Life Magazine for $150,000, giving $25,000 to the widow of a policeman who was killed by the fleeing Oswald.

That would set off a decades-long convolution of legal battles, bootleg copies, court rulings and acts of Congress, questions of authenticity, charges of profiteering and copyright infringement. Investigators, journalists and legions of conspiracy spinners would make it arguably the most dissected strip of film in history, pulling from its colored shadows Umbrella Man, Black Dog Man and other icons of intrigue.

To many assassination scholars, Zapruder’s biggest impact was to cast doubt on the central conclusion of the government investigation: the lone-gunman theory. The gruesome climax of the sequence shows a plume of gore erupting from the front of Kennedy’s head. Oswald fired from behind.

That spawned debates over neuro-spasms and the jet effect that have never gone away. But because the issue is never even mentioned in the Warren Commission report, the official version was hopelessly compromised for many.

“The climax of the film is not the scenario that they put forward,” Thompson said. “If it weren’t for the film, the logical problems of the Warren Commission would not have been exposed.”

Thompson, a Yale-educated former professor of philosophy who worked on Life’s major investigation of the assassination, thinks the film is still yielding bits of truth. Digitally enhanced versions abound on the Internet and, when combined with acoustic evidence, Zapruder may yet provide something definitive, he said.

“What we’re leaning now, 50 years after, is how good the Zapruder film is at telling us what happened,” he said.

Zapruder died of cancer in 1970. The battle over who shot JFK and who controlled the film of the assassination raged on. Geraldo Rivera showed it on television in 1975, frame 313 and all. Oliver Stone put it on the wide screen in 1991’s “JFK.”

Life magazine sold the rights back to Zapruder’s family for $1 in 1975. The federal government took the original as an official “assassination record,” paying the family $16 million under eminent domain in 1999. The family donated the copyright and their own archive to the Sixth Floor Museum in the former Texas School Book Depository in 2000.

In all, Zapruder’s brief and eternal collision with history produced an artifact steeped in evidence and uncertainty, perfectly preserving chaos captured at 18 frames per second.

“It embodies all the contradictions that can’t be resolved,” said Alexandra Zapruder. “Not just the forensics and the ballistics, but the cultural problems, our inability to make sense of the senseless.”

It’s the movie that will never fade to black.

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