WASHINGTON — It was just before noon, in the last hours of a half-century wait for government documents about the assassination of John F. Kennedy, that the octogenarian Secret Service retiree shuffled into his first TMZ moment.

“A lot of people always have these different conspiracy theories,” a cameraman for TMZ, the gossip site, began, ambushing the former agent, Clint Hill, outside his hotel here on Thursday. “Do you sometimes hear it and wonder it yourself?”

Mr. Hill stared back at him.

“Never,” he said flatly. “I was there.”

The release of documents concerning Kennedy’s death has captivated historians both professional and amateur, returning a seminal moment of the modern presidency to the forefront of the American psyche.

Purveyors of conspiracy have long awaited the documents, eager to find in them any cracks in the authorities’ official account from Dallas.