Legal Question in Criminal Law in California

The course of action depends on when this occurred. But in any event, the proof of innocence would have to be very clear and conclusive to overcome a jury verdict of guilty. Something on the order of DNA evidence proving the accused was innocent, or the lying "victim's" admission that he or she lied, or any other evidence as convincing as those two.

Also, if the appeal period has not expired and you think one cause of the verdict was ineffective defense counsel, then an appeal on that basis might succeed, especially when combined with clear evidence of innocence.

If the defendant has not been sentenced, Penal Code 1181(8) allows a defendant to petition the trial court for a new trial based on newly discovered evidence that could not, with reasonable diligence, have been discovered and produced at the trial. Make sure they talk to their attorney about this before sentencing.