Cal. LAB § 405

Any property put up by any employee or applicant as a bond shall not be used for any purpose other than liquidating accounts between the employer and employee or for return to the employee or applicant and shall be held in trust for this purpose and not mingled with the property of the employer. No contract between the employer and employee or applicant shall abrogate the provisions of this section. Any employer or prospective employer, or agent or officer thereof, who misappropriates any such property, mingles it with his own, or uses it for any other purpose than that herein set forth is guilty of theft and shall be punished in accordance with the provisions of the Penal Code relating to theft.