Bubbles was largely based on a real Baltimore drug addict and police informant who went by that name. The real Bubbles, who would slur his speech much more than the fictional character, first started working with the cops near the early 1960's after being arrested for a burglary. He spent the next few decades as an informant, leading to the arrest of several hundred felons and getting paid at least $50 for each one caught. His near-photographic memory and ability to blend into the scene made him one of the best in the city. Eventually he would start using the hat method portrayed on the series, where he acted as if he was selling hats and would place one of a certain color on the head of those the police should arrest.
Michael Kenneth Williams, Andre Royo, Hassan Johnson and J.D. Williams appeared in Freeway: What We Do (2003). Many of the minor characters are played by real-life police officers, politicians and former criminals. In fact, many of the former criminals who act on the show were previously arrested by the real-life cops who act on the show.
Omar is the only character to not use major profanity. Michael Kenneth Williams was even given permission to remove any curse words from his dialogue if any mistakenly got put in.
The character of 'Bunk' Moreland is based on real-life Baltimore detective Oscar 'Rick'/'The Bunk' Requer. The real 'Bunk' also constantly chomped on a cigar and had a taste for fashion.