S19, E16: Alex Boone (Guest Star Neal Jones), a middle-aged writer, and David Sutton (Guest Star Michael Esper), a graduate student, are involved in a heated altercation. The following day, Boones dead body is found in a local park with no identification and the only eyewitness describing a blur running from the scene. Once detectives Lupo (Jeremy Sisto) and Bernard (Anthony Anderson) identify the victim, the story of his past begins to unfold. While searching for clues to solve the current murder case, the detectives discover that the victim was trying to expose information about a closed espionage case involving Suttons father and the Chinese government. Lupo and Bernard discover a family torn apart as a result of the espionage case and question Suttons sister Tracy (Guest Star Monica West), revealing his possible involvement in Boones murder. When the detectives believe they have gotten closer to revealing the truth, new information emerges and leads them in an entirely new direction. The case is further complicated when ADAs Michael Cutter (Linus Roache) and Connie Rubirosa (Alana de la Garza) must deal with the FBI and the U.S. Attorney's office as they try to bring the killer to justice. Also stars S. Epatha Merkerson and Sam Waterston.