Private security person means any private police, guard or any person who stands watch for security purposes. Private security persons may not begin performing private security services for a private security company until they have received a permit from the Department of Safety and Professional Services. The filing of an application for a permit is not authorization to practice. "Private security person" does not include off-duty law enforcement officers when employed by a person or entity and when such employment has been officially authorized by the officer's law enforcement employment department or agency as an appropriate extension of the officer's function; provided that the law enforcement agency gives the hiring person or entity a written statement concerning who is responsible or liable for the actions of the off-duty law enforcement officer while that person is performing services for the hiring person or entity.