This report (link below) clearly shows that by-standers stood between the book depository and the President and that a shooter in the book depository could not have shot the President.
Also, the President is shot frontally, not from the side or back; everyone can see his head strike back and parts of his skin and brain tissue fly onto the trunk of the car as his wife Jackie instinctively reaches for it.
The shots could have come from the triple overpass in front of the President’s limo, but the bullets would have had to pass through the windshield. I don’t see bullet holes in the windshield in any view of the shooting.
That only leaves the grassy knoll where shots could have been fired from, and in other film footage a police officer on a motorcycle rides up that knoll, indicating shots were fired from that direction. The police officer confronted a man there who had government credentials, but we hear no more of him. He should have been able to say there were no shooters there, but history gives no account of his events that day.
The telling part of the assassination, if you follow the testimony of people in the street that day at Dailey Plaza, was that there was the smell of gunpowder on the street. The shots did not come from the book depository.