Investigation into a hidden world where prisoners are kept in solitary confinement for years and years -- smaller than an ordinary parking spot. Tonight we'll see an undercover boss go behind bars... See More
Investigation into a hidden world where prisoners are kept in solitary confinement for years and years -- smaller than an ordinary parking spot. Tonight we'll see an undercover boss go behind bars posing as a prisoner to make a decision does this work. Or do inmates come out more dangerous than they -- -- Here's ABC's Dan Harris. You are looking at six in -- 106. On the books as a dangerous armed robber. He is for Harry -- -- hell on earth solitary confinement. Before you meet its residents and it's just. Prison. Her work harder for being honest I think I've resorted to putting themselves and kill him -- -- -- as a prisoner 106 is moved into the I don't know that I have ever felt as vulnerable -- do right now. That thing even these officers don't know he's actually the secretary of corrections for the state of New Mexico. Greg markets now this is a policy speech the secretary is spending 48 hours on the inside. To decide how to reform the State's use of solitaire and -- -- people back to our neighborhoods where someone can. I can't allow that. It's the kind of confinement Freddie -- lives every day this is my home repair. Growing up -- as a wanted to be an astronaut but at age thirteen he got caught up in gangs how many murders did you commit. -- prison officials have kept him in a cell like this every day for the past ten years. These four walls are all he's got he knows every crack every inch of peeling paint. What does that do you had it is. Perpetual misery. It's -- it's monotony its reputation. He says the only way to survive in here is to establish a strict routine. A sort of imitation of life. I exercise. Battery to law fighting how to books I probably would are gone and seen. As for secretary market -- 24 hours into his day and claustrophobia. Is setting in feel like this was squeezing down on me. Inmates get an hour a day outside -- yourself. Just -- -- -- here earth. Cells. By two guards is probably the only human contact you know things. Critics point to studies which they say show that solitary confinement can result in brain damage similar to that made by head trauma. We are social animals were built for interaction. Take that away critics say inmates can literally lose their minds as the secretary finally gets released he says he now believes that solitary should continue. To be used. But only for the most dangerous are there were -- business -- later Freddie radios and seven other inmates are brought out of solitary. Here for the first time -- years. Real human contact. Great she's -- -- -- I think Dan Harris ABC news Santa Fe, New Mexico.
This transcript has been automatically generated and may not be 100% accurate.