http://www.youtube.com/watch?v=XY02Qkuc_f8
Secret Service left the motorcade before the assassination happened.
No doubt that LBJ was behind such a cover-up and a crime which needed the cooperation of the secret service, the FBI and most of the agencies. I am very pro-US but in that case, it was without any doubt an inside job. No foreign government or organization could control the inquiry and Kennedy’s bodyguards as it happened.
When I visited Daily Plaza in 2006, almost anyone around the crime scene knew for a while that “Dallas had killed JFK and let his man to the White House”.