Legal Question in Criminal Law in California

In any criminal case, the prosecution will have to prove identity, not just a name. Your partner's attorney (whether private or public defender) should b challenging the ID well before the trial. Fingerprints, booking photos, line up motions, etc may clear this up.

If your partner can't afford to hire his own attorney, the judge will appoint the public defender when he goes to court. Identity mix-ups are pretty common in the criminal courts and his lawyer should be able to resolve it easily.

This is not a do-it-yourself project, like fixing a leaky faucet, that you should attempt to resolve yourself. The District Attorney's office was actually trying to protect your partner by refusing to speak to you; criminal defendants who contact law enforcement, instead of letting their lawyers handle things, usually make the situation worse.

Your partner should also ask his lawyer about a factual finding of innocence, where the judge states he didn't commit the offense. That's better than a dismissal for lack of evidence.