Basically, she thinks you are hiding money. The job of the CPA is to find out how you're hiding it and where. To do that he/she will have to get an understanding of how your business works on a financial level and go from there. Depending on how much money your ex has to use this could entail a review of every document related to the business going back for years. If you aren't hiding money then it's just a long formality that will cost your ex through the teeth. If you are, well then hopefully you're smarter than the accountant. Of course, she'd need a court order before you have to comply with the forensic accountant's investigation.