S18, E12: The police break up a dog-fighting ring, and discover a woman's finger inside one of the dead animals. The finger is identified as belonging to Lauren Vance, soon-to-be ex-wife of Marty Vance (guest star Adam Rothenberg), after her body turns up near a dog breeder. Since Lauren and her husband were in the process of divorce proceedings, Detectives Ed Green (Jesse L. Martin) and Cyrus Lupo (Jeremy Sisto) initially suspect Marty as the brutal murderer. Marty was involved in the dog-fighting ring with friend and business partner Jay Carlin (guest star David Harbour), an extremely wealthy wine dealer. As the investigation unfolds, the detectives plot to trick an ambitious reporter, Dawn Talley (guest star Lara Flynn Boyle), who uses her sexuality to try to break the case. Turns out Jay's business is a scam, which leads prosecutors Michael Cutter (Linus Roache) and Connie Rubirosa (Alana De La Garza) to a new suspect. Also starring: Sam Waterston and S. Epatha Merkerson.