California Code, Food and Agricultural Code (Formerly Agricultural Code) - FAC § 23043

(a) Stop any conveyance which is transporting on any public thoroughfare any horse, mule, burro, or sheep, the carcass of any such animal which has the skin on it, or the hide or skin of any such animal.

(b) Take possession of any horse, mule, burro, or sheep, the carcass of any such animal which has the hide or skin on it, or the hide or skin of any such animal and hold it for 30 days pending an investigation.