Cal. Labor Code § 5908

(a) After the taking of additional evidence and a consideration of all of the facts the appeals board may affirm, rescind, alter, or amend the original order, decision, or award. An order, decision, or award made following reconsideration which affirms, rescinds, alters, or amends the original order, decision, or award shall be made by the appeals board but shall not affect any right or the enforcement of any right arising from or by virtue of the original order, decision, or award, unless so ordered by the appeals board. (b) In any case where the appeals board rescinds or reduces an order, decision, or award on the grounds specified in paragraph (b) of Section 5903, the appeals board shall refer the case to the Bureau of Fraudulent Claims pursuant to Article 4 (commencing with Section 12990) of Chapter 2 of Division 3 of the Insurance Code, if the employer is insured, or to the district attorney of the county in which the fraud occurred if the employer is self-insured.