Your comment is being downvoted because if this statement is true (and you reckon it's BS), then it provides a strong incentive to lock more people up, and lock them up for longer - i.e. political and economic motives to lock people up, rather than reasons tied to justice. Reminds me of 'The Shawshank Redemption':
"Warden Norton eventually creates a scheme to use prison labor for public works, undercutting the cost of skilled labor and receiving kickbacks for it. Norton has Andy launder the money under a false identity, in exchange for allowing Andy to keep his private cell and to continue maintaining the library. Brooks, freed on parole, is unable to adjust to the outside world, and hangs himself; Andy dedicates the expanded library to him. In 1965, Tommy Williams (Gil Bellows) is incarcerated on robbery charges. He is brought into Andy and Red's circle of friends, and Andy assists him in getting his GED. Upon learning of the crime of which Andy was convicted, Tommy reveals that one of his old prison-mates, Elmo Blatch (Bill Bolender) had claimed to have committed a nearly identical murder. Norton, fearing what Andy might do if released, puts him into solitary confinement and has Tommy killed by Hadley, claiming he was an escapee."
In other words, the warden killed a prisoner who had information that would have freed the main character. The warden had the prisoner with that information killed, as he wanted the main character around as he was a former banker who was helping him to commit bank fraud.