“Private merchant police,” “guard service” and “patrol service” mean any person, firm or corporation who engages in a business for hire to provide a protection service for the property of others and whose duties and activities in that connection include patrolling, guarding or watching the property of a subscriber, purchaser or client under contract or agreement to provide a protective service.

“Security officer” means any person regularly employed by a person, firm or corporation, and whose duties, in addition to property of the employer, include conducting investigations concerning the reputation or character of employers or prospective employers, and investigations concerning the location of property of the employer that becomes lost or stolen.

“Watchman” means any person regularly employed by a person, firm or corporation whose duties and activities consist of patrolling, guarding or watching the property of his/her employer.