|Remember the Devil|
|Season 4, Episode 17|
|Airdate||March 22, 2017|
|Written by||Mike Weiss|
|Directed by||Rohn Schmidt|
|Emotional Proximity||Little Bit of Light|
Remember the Devil is the seventeenth episode of the forth season and the 78th overall episode of Chicago P.D.
The Intelligence unit investigates a woman being held captive in a shipping container who refuses to help find the suspect involved. When a video goes viral, the team realizes that there is a second hostage, and they race against time to find her. Meanwhile an ex-girlfriend of Halstead's turns up in Chicago and drops the bombshell that they are still married, and Olinsky returns to work following his daughter's death.