I watched a video not long ago that presented this theory. In the video, you can see the driver turn around when the fatal shot is fired, at which time Kennedy's head jerked back, meaning that shot came from in front of him and not from the book depository. Now, did it come from the driver, or the grassy knoll? In the video I watched the statement was made that Jackie knew it came from the driver, which is why she climbed out of the seat because she didn't want to be killed too.