After the assassination of JFK, President Lyndon B. Johnson established the President Commission on the Assassination of President Kennedy and appointed Chief Justice Warren to lead the investigation. The following year, the investigation was finished and the entire report was made available to the public. It ruled that Lee Harvey Oswald was the assassin and he was acting alone. Since the official investigation concluded that Oswald was the killer, citizens should believe this theory. The U.S. government thoroughly investigated and researched all possibilities and aspects of the case, so their opinion should be trusted.
The conclusion from the Warren Commission cannot be trusted because the government excluded relevant information from the report. Warren denied other Commissioners access to Kennedy's autopsy photos because he believed them to be "too disturbing." There have also been members of the Kennedy family and other politicians who have spoken publically about disagreeing with the conclusions of the Warren Commission.
[P1] The Warren Commission was established to investigate JFK's assassination. [P2] The Warren Commission concluded that Lee Harvey Oswald was responsible for assassinating JFK. [P3] Therefore, Lee Harvey Oswald killed JFK.
Rejecting the premises
[Rejecting P3] This does not necessarily mean that Lee Harvey Oswald did it, as the report left things out.