142 Wellington Place

Fourteen years after the end of World War II, former RAF fighter pilot Ben Benison gets a frantic phone call from Celia, the wife of his best friend, Don. It seems Don has been unfaithful, and the proof stands in the hallway of the couple's home: Ada Hamilton, a young, fragile, pregnant girl who clutches love letters written in Don's hand. Unfortunately, Don is in London, and Celia wants Ben to find out if her husband truly is a liar and a cheat.
Ben heads up to London to confront his old friend and then returns to Celia's house to deliver the sad news that Don has admitted to the affair. But then things take a strange and sudden turn. Two police inspectors arrive minutes later and reveal that Don's body has been found in his rooming house at 142 Wellington Place. Whether his death was by suicide or murder, they can't-or, more accurately, won't-say.
The authorities open up an inquest into Don's death, and Ben accompanies the police back to London, where they interview witnesses and gather evidence. Tracking down Don's mistress complicates things and there is a great twist when a second "Miss Hamilton" turns up. Something is certainly rotten at 142 Wellington Place.