The Brethren — John Grisham

They call themselves the Brethren: three disgraced former judges doing time in a federal prison in Florida. Meeting daily, these judges-turned-felons reminisce about old court cases, and contemplate where they went wrong in their lives. They decide to use their jail time in a more profitable manner: devising an extortion scam so perfect that they won't know why it fell apart until it's too late.