(a) If a person employed by a library or a person charged with the supervision thereof has reason to believe that a person has committed or has attempted to commit any offense under this subchapter or that the person has concealed any library material upon his or her person or within his or her belongings, then the person may be detained and questioned in a reasonable manner for the purpose of ascertaining whether or not an offense has been committed.
(b) The detention and questioning shall not render the employee civilly liable for slander, false arrest, false imprisonment, malicious prosecution, unlawful detention, or otherwise, if the library employee or person charged with the supervision of the library acts in good faith and in a reasonable manner.
(c) For the purpose of ascertaining whether or not an offense has been committed, libraries, museums, archives, and other depositories may establish policies that require persons entering and exiting the premises wherein library materials are maintained to open and disclose the contents of any bags, purses, briefcases, and other containers which are being carried by or are in the possession of the persons.