Fontana and Green look into the murder of a mob accountant. When his widow (Amy Ryan) messes up on the witness stand, the burglar who killed him is acquitted. Later the victim's best friend, a former cop, shoots him. McCoy and Borgia aren't buying his claim it was self-defense. He threatens to lie on the stand about planting evidence in past murder cases, jeopardizing dozens of convictions. To get a guilty verdict, Jack grants the widow immunity to testify...when she discloses the revenge killing was her plan all along.We're talking about Law & Order season 16 episode 12 "Family Friend." Our guest is Shadow and Bone and Hell Bent author Leigh Bardugo.This episode takes cues from the evidence planting scandal for New York State Police Troop C.