If you commence litigation, you should be able to obtain the evidence through discovery.
Whether or not you have a viable case is something best resolved through a consultation with a California employment lawyer.
I am curious about this:That is, why was it necessary for you to conduct your own investigation before you could conclude that you were not responsible for the alleged theft? Obviously, you will be in a better position for litigation if I am misunderstanding your remarks, and the reason you knew that you weren't responsible is that you have never stolen any money from your employer.Quoting schuels

