If the "someone" is an employee, you are in the United States and you are talking about embezzlement than you can talk to the district attorney. In California depending on the amount it's either treated like petty theft or grand theft.
Most of the time though for a district attorney to want to take action though it really needs to be around $1,000,000+ embezzled because of prison overcrowding and the amount of work that has to go into criminal prosecution.
A good one.
An investigation will need to be conducted, if the thief is even caught, there will be a lengthy prosecution process, and it will likely end up costing you a shit ton of money.
If it was an inside job, I would try and contact a business/corporate attorney that specializes in white collar crime.
You don't need an attorney. You need a hitman 😾