Cal. Bus. & Prof. Code § 18826

Whenever any promoter fails to make a report of any contest or wrestling exhibition within the period prescribed by this chapter, or whenever such report is unsatisfactory to the commission, the executive officer, or his or her duly authorized representative may examine, or cause to be examined, the books and records of the promoter and any other persons or organizations, and subpoena and examine under oath, such persons for the purpose of determining the total amount of the gross receipts for any contest or wrestling exhibition and the amount of tax due pursuant to this chapter, which tax he or she may fix and determine as a result of such examination.