California Code, Penal Code - PEN § 831.4

(a)(1) A sheriff's or police security officer is a public officer, employed by the sheriff of a county, a police chief of a city police department, or a police chief of a police division that is within a city department and that operates independently of the city police department commanded by the police chief of a city, whose primary duty is the security of locations or facilities as directed by the sheriff or police chief. The duties of a sheriff's or police security officer shall be limited to the physical security and protection of properties owned, operated, controlled, or administered by the county or city, or any municipality or special district contracting for police services from the county or city pursuant to Section 54981 of the Government Code, or necessary duties with respect to the patrons, employees, and properties of the employing county, city, or contracting entities.

(2) In addition to the duties in paragraph (1), the duties of a security officer employed by the Chief of Police of the City of Sacramento or the Sheriff of the County of Sacramento may also include the physical security and protection of any properties owned, operated, or administered by a public agency, privately owned company, or nonprofit entity contracting for security services from the City or County of Sacramento, whose primary business supports national defense, or whose facility is qualified as a national critical infrastructure under federal law or by a federal agency, or that stores or manufactures material that, if stolen, vandalized, or otherwise compromised, may compromise national security or pose a danger to residents within the County of Sacramento. A contract entered into pursuant to this paragraph shall provide for full reimbursement to the City or County of Sacramento of the actual costs of providing those services, as determined by the county auditor or auditor-controller, or by the city.Before contracting for services pursuant to this paragraph, the Sacramento County Board of Supervisors or the governing board of the City of Sacramento shall discuss the contract and the requirements of this paragraph at a duly noticed public hearing.