In the season three finale, DEA investigator Neil Bishop takes the witness stand and delivers the confession that dismantles the prosecution's case against Julian La Cosse. Bishop reveals he was placed inside the DA's office by DEA agent James DeMarco, tracked Gloria Dayton to her apartment, and watched DeMarco slip into her building through an unmonitored entrance the night she died. After testifying, Bishop takes his own life in the courtroom. Julian is freed, Cisco's forensic work ties DeMarco to the Juárez Cartel, Mickey forces a city settlement, and a cartel photograph suggests DeMarco met his own end off the books. Four months later, Mickey is barely functioning until his daughter Hayley pulls him back — then he is pulled over, blood is found seeping from his trunk, and Sam Scales is dead inside it.

The finale resolves the central mur ...