some of the most violent gang attacks have taken place here, at california state prison corcoran's security housing unit or shu. we visited the shu's now vacant exercise yard which has been the scene of some of the prison's most brutal violence. ♪ correctional officers showed our cameras how they quell the violence with an arsenal of their own. one that includes nonlethal and lethal weaponry. >> first rounds we fire are wood blocks. hopefully the hurt will make them stop. we really have to escalate with our nonlethal options. we use what we call a scat round, which is really irritating. see, those are a little bit louder. the smoke you see there, that's cn gas. it's no fun. it messes up your sight. makes you, you know, makes your snot roll. and of course we have a lethal option. we have a mini-14 here the 223 round. we only use that as a last resort. >> today, california state prison corcoran no longer has to resort to such drastic measures to control violence in the shu yard. they close the yards down, and now inmates exercise in walk-alone areas called the cages. but even when officers ar

>> this is california state prison, corcoran. a maximum security prison that has housed some of the nation's most infamous criminals including charles manson and the founder of the mexican mafia. despite its reputation, violence doesn't come naturally to everyone at corcoran. >> i don't see myself as being like many of the people here. what i saw the longer i was here is there really is a thin line between them and me. >> before he was an inmate, stefan parro was a librarian. >> i'm here basically because i'm an alcoholic and i've done a lot of drugs, too. drugs are part of my story. >> parro's drug use resulted in a six-year sentence for crimes including burglary. >> at that time i had been married not very long. my wife was pregnant. the fact i couldn't stop drinking and i couldn't stop using, it was difficult to deal with the shame and guilt of all that. >> parro and his wife eventually separated, but he landed in prison for breaking into her home and stealing her credit cards to pay for drugs. >> i readily admitted to it. that

. >> during one of our shoots at california state prison corcoran our crew barely got a glimpse of manson before he covered up his window. a recent mug shot shows how much he has aged since first coming to prison in 1971. but his artwork provides a unique insight into his life behind bars. >> here's a scorpion that he's made. basically just taking thread from various types of items, socks and t-shirts and towels and he creates it and uses a marker to color it. this is probably one of the items that he makes the most of, would be scorpions and spiders. this is, i would assume, something like a harp and he's made it out of toilet paper, and newspaper. this looks like some dental floss, a small stick and probably for the coloring he used kool-aid to get the coloring for it. >> why do you guys have this stuff? >> he's not allowed to have it. occasionally we go through and do a cell searches, and just confiscate all items. he doesn't have a hobby card. other inmates try to sneak it out and put it on ebay and sell it and whatnot so we go in and confiscate it and dispose of it. >> how does he re

. >> when we visited california state prison corcoran for "extended stay," we came upon clarence lees he was moving into a new cell with an old friend from the neighborhood. a place he might never see again. lee was a veteran of the crips street gang and is serving a life sentence for murder. the majority of inmates in prison belong to gangs. >> welcome into our little casa. >> lee's old friend reginald maiden who preferred to be called terry was in a distinct minority. >> go to school together. help each other with schoolwork. go to chow together. i have no problem sitting with terry. i have no problem doing whatever with terry because i look at him as a human. i understand all of the things he went through. to others it seems like we're more than homeys because they don't understand how long i've known terry. >> terry was a very overt transgender inmate. then we meet clarence who comes off as this very strong, straight-looking guy. and because terry was constantly running into problems with his cellmates, he needed protection, for lack of a better word, and clarence was willing to

. >> duncan was serving 28 years for home invasion, kidnapping, and robbery at california state prison corcoran. it was the culmination of a criminal career that began at a very young age. >> i came from a good home. i can't say that i had a bad childhood. i just got mixed up with the wrong people. i started committing petty crimes when i was a kid because i actually did get strung out on heroin. my first shot was probably when i was 10 or 11 years old. >> duncan had spent most of his life incarcerated. in that time, he developed a reputation as an inmate to fear. >> these are some weapons that they say they discovered in a cell that i once occupied, allegedly. myself, personally, i'm a nice guy and i don't believe in violence. that's a damn lie. it was my responsibility on the yard to ensure that, one, our people were not harmed by another race. i took care of the drug debts if one of our people became delinquent in a drug debt to another race, it was my responsibility to either cover their drug debt or have them stabbed, in which case we would send one of ours to stab them. >> duncan's loyalt

. ♪ ♪ as we sing holy holy holy >>> when we met brian at california state prison corcoran, we had a prettyhunch that the origin of his nickname would play a major part in his story. >> my nickname is lefty. never been called lefty, it's because i have one arm. at 18 i was the victim of a drunk driving accident when i was in the air force. >> the other thing that was significant about brian to me was he was the height of irony on a lot of levels. he was a good example as to why you don't want to take justice into your own hands. his crime was that of a vigilante. >> you know being a christian means you don't have to be scared of your past because your sins, no matter how ugly they are, and we have some ugly ones in this room -- >> he is an inmate preacher at the prison's chapel and can trace the ugliest of his sins to a bizarre series of events that began with the loss of his arm. >> after the air force medically retired me, i retired to little rock, arkansas, started selling clothes in the mall. all i thought about all day long was having one arm, being in the big city where i didn't know