According to On The Trail Of The Assassins by Jim Garrison:
"The last-minute change in the parade route in Dallas was highly suspicious and raised serious questions about the mayor of Dallas, Earle Cabell, and his brother, former Deputy Director of the C.I.A., Charles Cabell, who had been fired over the Bay of Pigs fiasco [of 1961]. The parade route change, along with other leads pointing to the C.I.A., had been covered up neatly by the Warren Commission and its point man for intelligence issues, former C.I.A. Director Allen Dulles."
Former New Orleans D.A. Garrison also recalled that:
"The original route scheduled for the motorcade did not go right past the Texas School Book Depository where Oswald had been working...In fact, as late as the morning of the assassination the motorcade route was still diagrammed on the front page of the Dallas Morning News as continuing on Main Street to the center of Dealy Plaza."
Coincidentally, Garrison noted in his book that when he "pulled open my middle desk drawer and took out a copy of the Dallas Morning News front page that had been introduced as a `Warren Commission exhibit,'" he discovered that "on five-sixths of the Dallas Morning News where the diagram of the motorcade route was supposed to be" there "was nothing but a large square of solid gray."
On The Trail Of The Assassins also noted that although "there are also people who say that a map of the amended route was published sometime before November 22," coincidentally, "no such document has surfaced."
After JFK fired C.I.A. Deputy Director Charles Pearre Cabell, "General Cabell's subsequent hatred of John Kennedy became an open secret in Washington," according to Garrison. As Garrison also noted in his book:
"In most countries, a powerful individual who has been in open conflict with a national leader who was later assassinated would receive at least a modicum of attention in the course of the posthumous inquiry...Certainly a powerful individual who also held a top position in a major espionage apparatus and had been at odds with the departed leader would be high on the list of suspects."
Yet, according to Garrison, "General Cabell, who fit the description perfectly, was never even called as a witness before the Warren Commission."