code 2. >> during the months we spent in san antonio, to shoot our "extended stay" series, we discovered a source inside the county jail as well. a bitter gang rivalry. and in the middle of it was officer rodriguez, the jail's gang investigator. >> you're next. lock you down. >> for what? >> i saw you throw your -- >> new york i was putting my shirt up. >> s.o.s. >> i was watching it. >> officer rodrigu is an expert on gangs and loves being an expert on gangs. he's fascinated with the political structure, fascinated with how gangs are changing. he's tough but fair. talks to the gang members in a very respectful way. >> can't stay in population. ever been part of a gang before