Luther says to his young officer, "Contact Detective Munch in New York; he works in the Special Victims Unit." Detective John Munch is a character in the U.S crime drama Law & Order: Special Victims Unit.
At the beginning of the episode it is stated that previous murders took place in Isleworth, Whitton and West Drayfield. The first two are towns in west London but West Drayfield does not exist.
Goof: Luther suffers a laceration over his left eye after being hit by Owen's rifle. The wound bleeds profusely. During the scene as the camera switches focus between Luther and Owen the blood and wound almost vanish.
Goof: At the staged crime scene the emergency lights were turned off. When the shooting starts the lights are suddenly on again.