The U.S. Justice Department has issued subpoenas to California officials in an escalation of its scrutiny of local election administration. The subpoenas were issued by all four U.S. attorneys in California Thursday, according to a person familiar with the matter who insisted on anonymity to discuss an ongoing investigation. On Thursday, a federal judge also appointed a special master to evaluate the administration's claims. The Justice Department insists it's trying to prevent fraudulent voting. The administration’s appeal is now before the 9th Circuit Court of Appeals. Millions of Californians have already voted.