As Gus (played by Clark Johnson) enters the bar, he passes a man saying, "I used to own a bar". The man is played by Richard Belzer, who - as John Munch in Homicide: Life on the Street (1993) co-owned a bar with Meldrick Lewis - played by Clark Johnson.
Det. Vernon Holley is seen reading "Generation Kill". Show writers David Simon and Ed Burns, adapted this novel into an HBO mini-series (Generation Kill (2008)).