In dozens of police lawsuits across the decades, lawyers for the city have denied the existence of even an unwritten code among CPD officers that dictates Chicago cops turn a blind eye to abuses by their fellow officers. But in recent months, Mayor Rahm Emanuel has acknowledged the code in public statements as he has tried to tamp down public furor over high-profile police shootings and embrace reform of his troubled police force.

Emanuel may have to repeat — and explain — those remarks on the witness stand in a whistleblower lawsuit, in which two Chicago Police officers claim fellow officers punished them for breaking the code when they tipped off federal investigators about corruption in the Narcotics Unit nearly a decade ago.

Despite the mayor's public acknowledgement of the "thin blue line" of silence that cops dare not cross, lawyers for the city as recently as Wednesday tried to bar lawyers for the two officers from even using the words "code of silence" in front of a jury.