Within the last year, an FBI agent in Dallas described finding a nearly pristine bullet on top of the trunk of JFK's limo and placing it on a stretcher at the hospital. The bullet was likely an undercharged round that had hit Kennedy in the upper right back and popped out, leaving a shallow wound. This became the so-called "magic bullet" that the Warren Commission falsely claimed to have wounded both Kennedy and Connally.
As it was, the FBI and Warren Commission had too many gun shots, wounds, and bullets to account for if Oswald was the lone assassin. To overcome this problem, the Zapruder film, the autopsy, the autopsy photos, and witness testimony were tampered with to fit the Oswald as lone gunman theory.