Cal. Penal Code § 852.3

If an arrest is made in this State by a peace officer of another State in accordance with the provisions of section 852.2 of this code, he shall without unnecessary delay take the person arrested before a magistrate of the county in which the arrest was made, who shall conduct a hearing for the purpose of determining the lawfulness of the arrest. If the magistrate determines that the arrest was lawful, he shall commit the person arrested to await a reasonable time for the issuance of an extradition warrant by the Governor of this State or admit him to bail for such purpose. If the magistrate determines that the arrest was unlawful he shall discharge the person arrested.