Here´s a pretty convincing video made by Bob Harris saying that at least one bullet was fired from the Daltex Building (not the building Lee Harvey Oswald was in) and struck JFK.
I´m not saying the Mafia was involved in killing JFK, but If what Bob Harris is saying in this video is true, then there certainly was a conspracy to kill JFK. And I belive Oswald was part of it. In addition to the shooter in the Daltex Building, numerous of witnesse also heard shots coming from behind a fence on the famous grassy knoll.