Nick Wechsler

When a sex offender is found dead and mutilated, Intelligence look into a private police force that may be covering up illegal activities; Halstead runs a DNA check on Jimmy and discovers he is not Erin's father.

When Olinsky catches wind of a grieving father looking to avenge his daughter's death, he goes undercover as a hit man.

Halstead goes undercover to investigate the death of a teen who ran away from a treatment centre for troubled girls.

The team investigate a fatal home explosion that left the remains of a charred body, one injured survivor, and no witnesses.

The investigation of a jogger's brutal murder in a park is blocked by a church offering sanctuary to the prime suspects; Rixton goes behind Voight's back to question a gang member in relation to the case.

After the body of a young woman is found with multiple gunshot wounds, Intelligence identify links to other deaths and realise they are dealing with a serial killer; Lindsay finally meets her biological father.