Updated

Former NYPD police commissioner and inmate Bernard Kerik has reinvented himself as a crusader for prison reform.

Kerik has detailed his own time behind bars and spells out his agenda in a new book titled "From Jailer to Jailed."

Kerik also once ran New York City's jail system and was nominated for U.S. Homeland Security secretary before landing in prison on a fraud conviction in 2009. He tells The Associated Press that he walked out in 2013 determined to fix some of the injustices he saw from the inside.

The 59-year-old Kerik still says he was railroaded by overzealous prosecutors.