Va. Code § 42.1-73.1
A library or agent or employee of the library causing the arrest of any person pursuant to the provisions of § 42.1-73, shall not be held civilly liable for unlawful detention, slander, malicious prosecution, false imprisonment, false arrest, or assault and battery of the person so arrested, whether such arrest takes place on the premises of the library or after close pursuit from such premises by such agent or employee, if, in causing the arrest of such person, the library or agent or employee of the library had at the time of such arrest probable cause to believe that the person committed willful concealment of books or other library property.
The activation of an electronic article surveillance device as a result of a person exiting the premises or an area within the premises of a library where an electronic article surveillance device is located shall constitute probable cause for the detention of such person by such library or agent or employee of the library, provided that such person is detained only in a reasonable manner and only for such time as is necessary for an inquiry into the circumstances surrounding the activation of the device, and provided that clear and visible notice is posted at each exit and location within the premises where such device is located indicating the presence of an anti-theft device. For purposes of this section, "electronic article surveillance device" means an electronic device designed and operated for the purpose of detecting the removal from the premises or a protected area within such premises, of any specially marked or tagged book or other library property.
Va. Code § 42.1-73.1