When you look at the Zapruder film, there is a lot going on. To say THIS IS DEFINITELY WHEN ONE OF THE SHOTS OCCURRED, you need a bit more information than just a rapid movement seen in the film that "MIGHT be due to a shot" IF you do that kind of analysis, your work is little more than a series of guesses. But once you know for sure that there is an audio recording of the shots then you know it's analysis gives significant additional information. And with that additional knowledge, you can solve the "mystery" all the way to WHO and WHY JFK was killed even though the lies have convinced millions of people they will never know the truth.
How do I know the police audio recording did record the sounds of the gunshots? There are definitely two times in the Zapruder film that we can see reactions due to gunshots.
Frame 224 Connally and JFK react to a gunshot
Frame 313 JFK is shot in the head
The FBI measured the Zapruder camera film speed as 18.3 frames per second. A simple calculation shows the time between frames 224 and 313 is 4.8 seconds.
If we look at the acoustical analysis results, we see the time between shots 3 and 4 is 4.8 seconds. 
THIS IS A BIG DEAL! It shows that the audio recording likely did record the sounds of the shots otherwise you are forced to argue that the audio experts guessed 4.8 seconds for the time between shots exactly like the Zapruder film shows.
Then I looked at the time in the audio analysis and saw that the last shot was fired a split second after the JFK head shot. AND WHAT DO YOU SEE THEN?
The gov't and virtually everyone the planet Earth thought that Gov. Connally was pulled over into Nellie's lap as she was trying to save his life. But when you look closer, you see Gov Connally not pulled over into her lap but instead violently thrown forward. The audio analysis also gives us an idea WHERE the last shot was fired from and that was from the Texas School Book Depository.
Here is what happened for the last two shots:
Gov Connally reacted and turned to look over his right shoulder right after he emerged from the sign .
For several seconds we see JFK holding his neck and slumping, obviously wounded but also obviously not fatally. Two of the gunmen aimed for another shot.
1)The first fired from the right front hits JFK in the head and drives him back and to the left directly away from the gunman on the grassy knoll
2) The shooter from behind in the Texas School Book Depository (TSBD) fired a split second later, the shot missed JFK's head and hit Connally in the back, knocking him violently forward in his seat, directly away from the gunman in the TSBD.
http://i17.photobucket.com/albums/b97/Cortex_2005/zapruder.gif
When you UNDERSTAND what happened during the shooting, you then look at the government's evidence and their explanations of the shooting scenario. Most everyone has tried to find a consistent scenario that would fit with the autopsy photographs, it would explain why people in Parkland thought they saw a large hole in the back of JFK's head, it would explain why so many people disagreed with so much of the Warren Comm. report. But instead, the audio evidence is inconsistent with a significant amount of evidence provided by the US government which means that because we have shown the audio evidence is valid, we have also shown that significant amounts of evidence is FORGED.
Saying it another way, only one thing can be right. Either the audio evidence is valid or the government's evidence is valid. One of them stinks to high heaven and because we know 4.8 seconds is common to both the audio recording and the Zapruder fim, we know the US government lied and forged to hide the truth.
Once you get to that point, you are then ready to start to figure out WHO was behind this brutal murder and scam of a cover up. There are only a handful of people who could pull off a huge lie like this. Once you prove the US government forged evidence, you soon know who was behind the assassination. Then you can start to look and understand how LHO was set up to look guilty beyond question. The US government will and did tell any lie to hide who killed JFK. But be very careful when you look at information, if you look at just what I showed you in this post and compare it to Bugliosi's RECLAIMING HISTORY, it will not match. There are some honest mistakes that have hid the truth but there are also huge lies too. You must identify and correct mistakes and lies before you can get right answers. That is one the reasons over a thousand books and documentaries have missed their target, they tried to use forged evidence to make it fit.