I'm sorry to hear of the situation.
While you may ask the employee to repay the money that was lost due to their negligence, CA law prohibits you from taking it from their wages.
In CA an employer cannot legally make such a deduction from wages if, by reason of mistake or accident a cash shortage, breakage, or loss of company property/equipment occurs. The California courts have held that losses occurring without any fault on the part of the employee or that are merely the result of simple negligence, are inevitable in almost any business operation and thus, the employer must bear such losses as a cost of doing business.
If you can prove that it was stolen, as opposed to simply have been thrown out with the trash accidentally, then you could sue the person who took it---but that would be the limit of your legal remedy---I'm sorry.
I understand that you may be disappointed by the Answer you received, as it was not particularly favorable to your situation, nor was it what I sensed you were hoping to hear. Had I been able to provide an Answer which might have given you a successful legal outcome, it would have been my pleasure to do so.
Because I help people here, like you, for a living---this is not a hobby for me, and I sincerely appreciate your abiding by the honor system as regards Accepting answers. I wish you and your family the best in your respective futures.
Would you be so kind as to Accept my Answer so that I may be compensated for assisting you? Bonuses for greatly informative and helpful answers are very much appreciated. Thanks Again,