Double Helix

While Peter Stone is cross-examining convicted murderer Zachariah, Zachariah brings up the fact that Peter Stone ended up following in the footsteps of his father by becoming a district attorney. When Peter Stone answers, he calls Zachariah "sir" at the end of a sentence that is critical of Zachariah. This is a direct reference to the character Ben Stone from Law & Order (Peter Stone's father); Ben Stone often called male witnesses "sir" when questioning them harshly. This is the first time in Chicago Justice that Peter Stone called someone "sir" in this way, and it may be unintentional on Peter's part, although it proves the deeper point that father and son are more similar than Peter would believe.

References Chicago Fire (2012)