On November 29, 1963, President Lyndon B. Johnson appoints a special commission to investigate the assassination of President John F. Kennedy, which had occurred a week earlier, on November 22, 1963, in Dallas, Texas.

According to his memoirs and biographer Doris Kearns Goodwin, Johnson knew he had to provide strong leadership in the wake of the shocking murder of President Kennedy. One of his first official acts was to initiate an investigation into the assassination. Johnson later wrote that, in the weeks after the assassination, the American public, and the government that he now headed was in a state of confusion and disorientation “like a bunch of cattle caught in a swamp.” He felt the weight of his new responsibility keenly “in a world that is never more than minutes away from catastrophe” and knew that “the whole world would be anxiously following every move I made.”

On November 29, Johnson issued Executive Order No. 11130, appointing the President’s Commission on the Assassination of President Kennedy–commonly referred to as the Warren Commission, after its leader, Chief Justice Earl Warren. Since the president’s assassin, Lee Harvey Oswald, was himself killed by Jack Ruby almost immediately after Oswald killed Kennedy, details of Oswald’s motive for the assassination remained murky.

During its almost year-long investigation, the Warren Commission reviewed reports by the Federal Bureau of Investigation, Secret Service, Department of State and the attorney general of Texas. It also poured over Oswald’s personal history, political affiliation and military record. Overall, the Warren Commission listened to the testimony of 552 witnesses and even traveled to Dallas several times to visit the site where Kennedy was shot. The commission concluded that Oswald had acted alone and that the Secret Service had made poor preparations for JFK’s visit to Dallas and had subsequently failed to sufficiently protect him.

The circumstances surrounding Kennedy’s death, however, have since given rise to several conspiracy theories involving such disparate characters as the Mafia, Cuban exiles, military leaders and even President Johnson. The Warren Commission’s conclusion that Oswald was a “lone gunman” failed to satisfy some who witnessed the attack and others whose research found conflicting details in the commission’s report.

Critics of the Warren Commission’s report believed that additional ballistics experts’ conclusions and a home movie shot at the scene disputed the theory that three bullets fired from Oswald’s gun could have caused Kennedy’s fatal wounds as well as the injuries to Texas Governor John Connally, who was riding with the president in an open car as it traveled through Dallas’ Dealey Plaza that fateful day. So persistent was the controversy that another congressional investigation was conducted in 1979. That committee agreed with the Warren Commission that Lee Harvey Oswald fired the shots that killed the president and that the Secret Service failed to protect Kennedy. It did, however, also allow for the possibility that a second gunman might have been involved, but did not pursue the matter further.