Oswald was arrested hours after the shooting. Two days later, he was shot and killed by a man named Jack Ruby.

But those findings have long been disputed by many Americans, and unsubstantiated claims about the involvement of the C.I.A., the mob and even Kennedy’s vice president, Lyndon B. Johnson, have circulated. Many people have questioned whether Oswald acted alone, and whether the assassination was a plot by Cuba or the Soviet Union.

In 2016, President Trump suggested that the father of Senator Ted Cruz of Texas was somehow involved in the killing. And in 2023, Robert F. Kennedy Jr., now the health and human services secretary, claimed there was “overwhelming evidence” that the C.I.A. had a role in his uncle’s murder.

According to the National Archives and Records Administration, about 99 percent of the Kennedy assassination records have already been unsealed. Still, the latest trove to be released may still hold clues for conspiracy theorists.

Here are some of the topics they may be hoping to learn more about.

The Warren Commission, which was established in 1963 to investigate the assassination, found that one of the bullets fired by Oswald struck the president, exited his throat and then hit Governor Connally, injuring his thigh, back, chest and wrist. That single bullet — called the “magic bullet” by those who found this chain of events implausible — was found on the stretcher that held the governor, the commission found.

Recently, Paul Landis, a Secret Service agent who was feet away from Kennedy when he was struck, added another layer of doubt to that story.

In a September 2023 interview with The New York Times, Landis said that he was the one who found the bullet, and it was not on a stretcher but lodged in the back of the limousine where Kennedy had been sitting.

Landis, who was not interviewed by the Warren Commission, stressed that he was not hoping to push a conspiracy theory. He had long believed Oswald was the lone gunman, he said, but “at this point, I’m beginning to doubt myself.”

In 1979, the House Select Committee on Assassinations released a report saying that conspirators were “likely” involved in Kennedy’s murder.

According to that committee, which based its findings on acoustic tests of Dallas police tapes, Oswald fired three shots from the sixth floor of the Texas School Book Depository and one more shot was fired from a grassy knoll in front of the president’s limousine. The report did not shed light on who those conspirators could have been.

The reliability of the acoustic findings has since been questioned, and the findings of the report have been largely undermined.

While investigations have found that both Oswald and Ruby acted alone, many conspiracy theories have flourished around the back stories of the two men.

Theorists have long contended that Oswald had ties to a foreign government or internal agencies in the United States. Many also questioned Oswald’s trip to Mexico City, and his visit to the Soviet and Cuban missions there, just weeks before the assassination. Oswald said he had traveled to Mexico to get visas from both embassies, but little is known about his time there.

Oswald, a former Marine, said he did not shoot the president and called himself a “patsy” set up by those who did.

He was shot dead by Ruby at close range while in police custody two days after the assassination. The Warren Commission found that Ruby did not know Oswald before killing him, but many still question Ruby’s motive, and whether or not there was a connection between the men.

Ruby was found guilty of murder in 1964. He appealed the ruling in 1966, but died the following year from a pulmonary embolism before his next trial began.