LBJ had a lot to gain. I seriously doubt he would have become president had the assasination not occured. I agree that the fatal shot that day came from the front. I also think that Oswald was just what he said, "a patsy". I don't think he fired a shot that day, but was set up to take the fall. LBJ was ruthless and at his worst on 11/22/63 (in my own personal, correct opinion).
Oswald killed Kennedy by himself...end of story.
Don't fall into this conspiracy trap the Democrats have fomented all these years in an effort to make his presidency more important than it was. People like to believe in a conspiracy because A) it's more fun, and B)the leftist media, teachers and cultural elites don't want to believe that some lone kook did there guy in.