Justice isn't about fairness. It isn't a system where victims can exact revenge on their tormentors, and it is not the place where serious crime is punished in appropriate measure. There are many examples where America's Justice has settled with offenders, in exchange for something. The criteria by which that something is weighted at time of reducing, or altogether eliminating, jail time remains a mystery. There isn't a table, or a set series of parameters guiding actions of the judiciary when criminals decide to "cooperate".