Straw Dog: Part 2 (S05E08)

Tony Greene is still incarcerated so the hunt is on for either the real killer or a copycat who has intimate knowledge of Greene's MO. The team trace the killer through Greene's ex-cell mate. He turns out to be one of Grace's fellow professionals who worked with Greene in prison and wanted to humiliate her professionally. Grace decides to confront him at his house. (iTunes)