Legal Question in Civil Rights Law in California

It depends on what the investigation finds, and whether the employer refers it to law enforcement. It would be helpful if your husband obtained a receipt for the deposit from the teller. There also might be video evidence that he dropped it off as most banks have several cameras around. You might have your husband talk with the branch manager to make sure that the bank secures the videos from that day. Perhaps he could watch the video(s) with the manager, in any case. You might gather your own bank records for the date(s) involved at least to assure that there was no unusual activity in your and your husband's account(s).

Certainly, the employer might suspend your husband without pay, pending the investigation, so you should be prepared for that possibility.

If the employer claims theft or fraud, then of course he can be criminally charged.

A little free advice: exercise the 5th Amendment right to SHUT UP and do NOT talk to police or anyone about the case except with and through an attorney. When charged with any crime, the proper questions are, can any evidence obtained in a test, search or statement be used against you, can you be convicted, and what can you do? If you don't know how to represent yourself effectively against an experienced prosecutor intending to convict, then hire an attorney who does, who will try to get a dismissal, charge reduction, diversion, programs, or other decent outcome through motions, plea bargain, or take it to trial if appropriate.