It shall be unlawful for any person, except a police officer or agent,
to kill, injure or attempt to kill or injure any animal which bears
a license tag for the current year. The exception to the preceding
sentence will be when any person sees an animal in the act of attacking
human beings, whether or not such animal bears the license tag required
by the licensing laws of this commonwealth. There shall be no liability
on such persons, in damages or otherwise, for such killing.