( Warren Brown ): Luther's loyal partner who must decide whether to testify against him.

Luther’s budding romance with Mary Day is repeatedly interrupted by the demands of the investigation. Key Characters & Cast

Luther investigates the deaths of Dani Lane and her husband. He realizes the killer is mimicking the 30-year-old "Shoreditch Creeper" murders.

DSU George Stark and DS Erin Gray continue their obsessive pursuit of Luther, trying to turn DS Justin Ripley against him.

Luther enters Stark’s lair, swipes his own file, and warns Stark that he will "take him down harder and faster" if Stark persists.