Chicago P.D. S04 E15 Favor, Affection, Malice Or Ill-will

Chicago P.D. S04 E15 Favor, Affection, Malice Or Ill-will : When Lindsay is tipped off about a father looking to avenge his daughter’s death, Olinsky goes undercover as a hitman for hire; and Gang Intelligence reinvestigates the original case. Meanwhile, Ruzek is placed on patrol duty after returning from his undercover assignment.