When it comes to uncovering employee theft, the best sources of information often are the people who work together and see one another day after day in all types of situations. Over time, they learn what constitutes "normal" behavior in co-workers and can spot abnormal behavior within minutes.

 So when a theft occurs, employees are often privy to impressions as well as information about others on staff that no background investigation could ever reveal. The key for the employee theft investigator is to show the thief's co-workers why it is in their best interest to share what they know; most often, they will help catch the thief. "No employer may cause an audio or video recording to be made in a restroom, locker room or room designed by an employer for changing clothes, unless authorized by the court order." Labor Code 435 (a.)

If an employer discharges an employee, the wages earned and unpaid at the time of discharge are due and payable immediately.
Labor Code 201 (a)  The purpose of this ad is to provide general information on the law, which is subject to change.

In any case, you should always use a professional employee theft investigator.