Robert F. Colesberry makes his final appearance as Detective Ray Cole in this episode. Colesberry died in 2004 following complications from cardiac surgery.
Dominic West's character McNulty is asked if he can do an English accent. He creates one which everyone deems to be mediocre. In real life, Dominic West is a native of England (but created a messy fake English accent - not his own - for this undercover role).
McNulty chooses the alias Cromwell. Dominic West would later play Oliver Cromwell in The Devil's Mistress (2008).