Chicago P.D. Season 4 Episode 8 : A Shot Heard Around the World
When a young officer is shot dead in the lobby of an apartment building, Intelligence looks to the latest known offenders who have threatened the police. But when a second officer is killed, the team finds that they are dealing with someone who is highly trained and knowledgeable. Voight works to keep the case contained as they deal with Chicago's ever-present war against the police. Meanwhile, Lindsay confronts Antonio about his new job with the State's Attorney.