In the scene where McNulty is paging through old case files, the camera zooms in on the signature for Detective Raymond Cole. Ray Cole was played by The Wire producer Robert F. Colesbury in seasons 1 and 2. Colesbury died in 2004. The season 4 finale and the series finale are dedicated to Colesbury.
The scene with Omar and Renaldo was filmed in La Perla disctrict of San Juan, Puerto Rico. The fort Castillo San Felipe del Morro can be seen in the distance.
The book Detective Frank Barlow is reading while Detective Jimmy McNulty is talking about red ribbons (referencing his made up links for homeless murders) is Generation Kill. The Wire's creator David Simon would later adapt this non-fiction book into a tv-mini series that was released for HBO in July 2008.
Banque Populaire des Antilles serves the French overseas departments and collectivities in the Caribbean.