Here's a few questions:

Why on earth would the previous owner expose himself to the potential liability of revealing his identity? Assuming that he was completely innocent and sold the car in good faith, your dispute is with your dealer/seller. How would an explanation of the details of the collision damage help your case?

In this case, the rule of caveat emptor (buyer beware) applies. Buying a car without a full VIN/Carfax report and a thorough inspection is nobody's fault but yours.

Dean