Yeah, right. I'll never believe this until things like the "magic bullet" and why Kennedy's head moved backwards when he was shot from behind are explained satisfactorily in relation to Oswald acting alone. Unfortunately, the only explanations for this require one to put aside all logic and simple physics. The actual truth is that the magic bullet could not have happened like they say and no one's head jerks in the same direction the bullet comes from after being hit.
On this 40th anniversary there's been a lot of this type talk and I don't know why. The only truth that is known is that as time goes by the real truth will likely never be known.
Kennedy's head didn't move in the same direction as the bullet. Conspiracy buffs keep saying: "Backward and to the left." Oswald's third shot was fired toward Kennedy from his (Kennedy's) right to his left (i.e. approaching from over Kennedy's right shoulder). If Kennedy's head had moved in the direction of the sixth-floor window, it would have been backward and to the right.
For every action there is an equal and oppopsite reaction. Kennedy moved backward and to the left while his brain and blood exploded out of his head forward and to the right. As far as I'm concerned, this explains why he moved backward and to the left.
Every time it is explained satisfactorily to you, you ignore it.
Go read this web page and follow the links. Then come back here and explain what is preventing you from accepting the single bullet fact (fact -- not theory).