Confessions are not reliable when it comes to parole
The New York Times - 11/13/2014
Contrary to the popular imagination, not all prisoners claim to be innocent. In fact, there is reason to think that most prisoners acknowledge their guilt of the crime of which they were convicted (while perhaps decrying the manner of investigation, prosecution, or sentencing).
Why? Because admitting guilt is essentially a prerequisite to receiving parole in many jurisdictions and parole is often the best, most immediate way to achieve liberty, albeit with strings attached.