The Mary Ferrell Foundation has an excellent essay on the connections between CIA and the JFK Assassination. If you’d like some background on this issue from a trustworthy source, this is the place to start. If you’re not ready to read a book on the assassination, at least take a look at this.
The Mary Ferrell Foundation is one of the most highly regarded collections of material on the JFK assassination. Even the National Archives links to it as one of their top 5 recommended resources.