protective search

The purpose of this limited search is not to discover evidence of crime, but to allow the officer to pursue his investigation without fear of violence, and thus the frisk for weapons might be equally necessary and reasonable, whether or not carrying a concealed weapon violated any applicable state law. So long as the officer is entitled to make a forcible stop, and has reason to believe that the suspect is armed and dangerous, he may conduct a weapons search limited in scope to this protective purpose.