If the above mentioned is San Quentin State Prison situated in
Marin County, California in United States of America, than my
believe is that Veteren Blues Artist The Legendary Mr. B. B. King
(Riley B. King) had once played his Blues there in 1990 and has
also released and album called 'B. B. King Live at San Quentin'.
You can check it out at the following WebPage:
http://en.wikipedia.org/wiki/Live_at_San_Quentin