Seriously, whose idea was it to free him after 10 years? The initial deal was "life sentence instead of death penalty" in exchange for information. So he flipped and got life. Why change the deal again after 10 years? Maybe he simply paid the parole board, i really can't think of another explanation, considering the fact he didn't tell anything new after those 10 years.
He was allowed to keep millions of dollars he had accumulated over the years, so paying off someone is probably what he did. There is no other explanation.
