GCPD Officer Whitman was an undercover Officer within Arkham City.
Batman: Arkham City
When Arkham City was developed, Commissioner James Gordon, due to his attempts to question Sharp about Arkham City either being ignored directly or placed in red tape, sent ten members of the 13th precinct to go undercover into Arkham City, one of them being Strickland.
Unfortunately, as soon as he and his fellow squad arrived in Arkham City, they were exposed via an information leak and captured by the Penguin's men. He was frozen by the Penguin's Ice Gun, which had formerly belonged to Mr. Freeze, along with his fellow officers Strickland and, after he tried to escape Forrester. Batman, after learning what happened to him from Forrester shortly after freeing him from his icy prison, rescued him.