Most people assume that those convicted of felonies were tried and found guilty by a jury of their peers. Not True. About 95 percent of all felony convictions in the United States are the result of plea bargains. Plea bargains are just a way of increasing conviction rates for the prosecution and reducing the load on the court system.
The way plea bargains were suppose to work and the way they actually work are quite different. The idea of the plea bargain was to keep cases of obvious guilt out of court by offering less jail time to the defendant if he pleads guilty to a lessor charge. In reality, it works quite different. The defendant is threatened with a number of charges that would add up to a lot of jail time. Then he's offered less jail time if he pleads guilty to a lesser charge.
The defendant, 95% of the time will go for the plea bargain rather going to trial with a public defender who spends most of his time negotiating plea deals rather actually going to court.
So when the prisoner says he's innocent of the crime he was convicted, he certainly may be telling the truth. In the eyes of the prisoner, the justice system is a sham and the likelihood that he will strike back is quite high. So when he's released in less than 3 years and he can't get a job, he feels justified in returning to crime.
Faqs | The Plea | FRONTLINE | PBS