>> sergeant roger ross is in charge of the osj unit that monitors all gang activity within the l.a. county jail system. >> los angeles county jail is unique in the fact that every gang in los angeles county ends up coming here. it doesn't matter if they're a black gang, an asian gang, a hispanic gang, or a white gang. if they're active in los angeles county and they get arrested, they end up coming to the los angeles county jail system. >> the osj unit must rely on communication to help prevent gang violence. >> solving crime is all about getting the information from somebody. it's not physical evidence. >> we ain't with nobody. it's just mainly a money thing. mainly we just doing our thing. everybody's doing their individual thing. >> you have had a history of feuding with who? blacks or hispanics? throughout the years over there. >> it's been a history of