The single shooter shot the president from above and behind him from the Texas Schoolbook Depository. The one bullet passed through the President’s head and then through Governor Connally’s back. If this is the case we would have to explain the location of the wounds orientation in the vehicle of both men, which would be very difficult.
There was one shooter in TSD for sure, and there might have been another one on the famous grassy knoll in front of the vehicle. Multiple shots would have been fired with one bullet hitting each man from the different locations. This theory is also difficult to prove because there is no clear cut evidence of another shooter that was located on the grassy knoll according to pictures and video evidence of the day.