now it's back to lock up. >>> among the challenges facing officials at kern valley state prison is therowing number of inmates with long-term sentences because typically this population is the most angry and the most violent. the staff knows the importance of keeping these men occupied. there are 1,300 inmates serving life sentences at kern valley. their crimes were often cold-blooded. >> i'm here for aggravated mayhem, attempted murder, kidnapping, and great bodily injury. >> i'm in here for the heat of passion. i caught my wife with somebody and killed her. >> for some of these inmates, the prospect of spending decades behind bars affects their ability to function. for others, a prison job can give them a sense of purpose. they work in the kitchen preparing and serving the food. they serve as porters, clerks, and barbers. marcus armstrong and jeffrey cattera know it's likely they'll never see the outside of prison again. >> january 13th, 1989, i committed my crime, was arrested the same day. it was a murder/robbery. i got life without the possibility of parole. stupid. stupid. i was

the night before. we were lucky to talk to him. escort! >> during our shoot at kern valley, inmate george johns serving eight years for being involved in a high-speed chase while on parole, started a fight in the cafeteria and was hit in the head by a wooden block. we met him the following morning. >> tell me the story. tell me what happened. >> i had a personal problem and i ran over and handled it and i didn't make it all of the way. i was in the chow hall eating, you know, i just got irritated and finally decided i don't like this guy. so i'm going to bite him. that's it. >> next thing you remember? >> they're dragging me out. telling me i got hit in the head with a block. >> let me see your head. >> the shooting left johns with seven staples in his head and a wound still caked with dried blood. he says the scar running toward the back of his head was the result of getting run over when he was younger. >> so you knew the other guy that you got into a fight with? >> yeah, kind of sort of. apparently i didn't like him. i was eating my dinner, eating a baked potato and grav

the next day. >> at kern valley state prison in california, we met inmate aaron yost. who participates in another illegal, yet very common, practice behind bars. tattooing. >> mine's artwork. i mean, i did this myself. >> where. >> huh? >> where. >> in a cell just like this. >> how? >> how? see this cassette player? got the motor out of it. attach a pin to it with the needle. spin a needle on the can, go back and forth. i'll make the ink. i'll burn plastic and baby oil. soot will come up. i'll collect the soot. mix it with shampoo until it's thick, black ink. >> tattooing in prison is illegal and poses a variety of health risks. but we've met countless inmates who have gotten their ink both on the outside and inside. many tattoos represent gang affiliation and are documented by prison officials. most of the rest have a meaning all their own. >> what my trip is is physics. my tattoos represent it. on my back of my legs it says quantum physics. i got an atom on my hand. i study what the ultimate nature of reality is. it soothes me. it soothes me to try and figure out wha

. >> aaron yost was 11 years into the latest sentence when we met him in kern valley state prison in california. he says his problems stem from a near lifelong abuse of drugs. >> i grew up with drugs. my parents were quote, unquote, hippies. both my parents dropped acid. my mom's dead now from a dug overdose. when i was 9 years old, i was rolling joints for mom and dad. >> yost's life is now largely confined to this cell, he shares with another inmate. >> i'm not comfortable like this. i don't like men. i like women. and to me it's disgusting. i'm still irritated. if i wake up in the morning, i'm agitated because i have to live with another man. >> now the closest yost comes to female companionship is his tattoos, some of which too graphic to show on television. >> that's all i dream about. that's all i got. >> i remember when we met aaron, the man was absolutely tattooed. just incredibly inked. if one word describes him, it's intense. just full of energy. i remember when my producer asked him, what's the daily routine. he started right in on telling us what it was all about. >> one

the main line, i'd be dead in a day. they would kill me right in front of an officer because it's a notch on their belt. >> we met earl hymer at california's kern valleyte prison. >> i have a 37-year sentence, lewd acts on a minor 14 years old. >> this was not his first time in prison nor his first sex offense. >> my wife deemed it necessary that i be arrested for attempted rape of your wife and not of a -- as weird as that sounds. you come home drunk and try to take it and she doesn't want it, that's still a criminal offense. >> hymer shares a cell with another convicted child molester, ray rowe, who is serving a 230-year sentence. even though he is in protective custody, rowe rarely leaves his cell out of fear for safety. >> i don't know whether someone is going to take me out before the day's over with. every time i go to chow. any time any sex offender goes to chow or goes out of their cell. and sometimes even in your cell. can i go to sleep with this person in here? you're pretty vulnerable when you're sound asleep. >> hymer and rowe have worked out an uneasy trust if not a friendship. >> we've managed to read or stay out of each other's way. >>