The title of the show, Whitehall 1212, refers to phone number of Scotland Yard, because even though it was American radio show, the stories presented were based on true crime that took place in United Kingdom. Chief Superintendent John Davidson, who actually was curator of the Black Museum, a famous collection of crime memorabilia kept in the Scotland Yard, was host of the show. Each episode was telling a different story linked to a different case, most of which later were identified by the fans of the show to be real cases that took place in pre-World War 2 Great Britain.
Actually there was also a radio show called The Black Museum, hosted by Orson Wells, which was based on more or less same set of cases, but the two shows had slightly different approach. In Whitehall 1212 whole story was told from perspective of policemen truing to solve the case, while The Black Museum was telling the stories behind the crime, the reasons of the killer, etc.
In total 44 episodes were produced, which were broadcasted between November 1951 and September 1952.
Can you solve a mystery like this one?