Cal. Penal Code § 26600

(a) Section 26500 does not apply to any sale, delivery, or transfer of firearms made to an authorized law enforcement representative of any city, county, city and county, or state, or of the federal government, for exclusive use by that governmental agency if, prior to the sale, delivery, or transfer of these firearms, written authorization from the head of the agency authorizing the transaction is presented to the person from whom the purchase, delivery, or transfer is being made. (b) Proper written authorization is defined as verifiable written certification from the head of the agency by which the purchaser or transferee is employed, identifying the employee as an individual authorized to conduct the transaction, and authorizing the transaction for the exclusive use of the agency by which that person is employed. (c) Within 10 days of the date a handgun, and commencing January 1, 2014, any firearm, is acquired by the agency, a record of the same shall be entered as an institutional weapon into the Automated Firearms System (AFS) via the California Law Enforcement Telecommunications System (CLETS) by the law enforcement or state agency. Any agency without access to AFS shall arrange with the sheriff of the county in which the agency is located to input this information via this system.