Recap / Fillmore A Forgotten Yesterday

• Chekhov's Gun: The episode features a minor subplot where O'Farrell tries to get the Safety Patrol to adopt communication wires for their use. At the end, it turns out Fillmore has been wearing one during Sonny's entire confession, giving the Safety Patrol the evidence needed to book him.
• Frame-Up: Sonny is revealed to have placed false evidence to gain Fillmore's trust.
• Manipulative Bastard: Sonny manipulated all of the events of the episode to get Fillmore to steal Rudy Teravall's ledger, which contained discs of stolen term papers, for him so he could sell them on the black market.
• Obstructive Bureaucrat: Representative Peabody's openly suspicious of Fillmore's old crime ties and Fillmore suspects he's ordering Fillmore off cases too. But its ultimately subverted: he and Fillmore team-up easily to take down Sonny.
• Spotting the Thread: Sonny's plan would've gone perfectly had he not forgotten to erase the anonymous call he made to Peabody on the cell phone he later lent to Fillmore.
• We Used to Be Friends: They were no longer on speaking terms to begin with, but Sonny's final betrayal of Fillmore ends any friendship they might still have had left.