The 13th Precinct of the Gotham City Police Department were sent into the prison of Arkham City, posing as inmates, by Commissioner Gordon. These men posed as men in the Penguin's criminal gang.
Because the GCPD Commissioner, James Gordon, was unable to learn anything about the newly developed Arkham City from Mayor Quincy Sharp due to him either ignoring him directly or placing red tape on the issue, Gordon handpicked ten police officers from the 13th precinct to form a squad to go undercover inside Arkham City to find out the true nature of the city-wide prison, despite Batman's warnings against the idea, and were also given the code of "Sarah" (obviously a reference to Gordon's second wife, Sarah Essen) in case they ever met up with Batman. The men were in Arkham City since the beginning, and eventually found a place in Penguin's gang.
Unfortunately, Hugo Strange exposed the team's true identities to Penguin, and the team was beaten and tortured by the gang as a result. During their imprisonment, they were also forced to wear yellow/brown pants and a white wifebeater shirt that had the words "Dead Cop" (and in the case of Elvis Jones, "Pig") written on the front in purple. One of the cops, Officer Best, was murdered by the Penguin. The remaining nine were eventually saved by Batman when he arrived at the Penguin's hideout to locate Mr. Freeze. The officers claimed the Iceberg Lounge as a base after Penguin's defeat, blocking it off from the museum. They later provided Batman with a mine detonation chip that they had discovered.