Voice in the fog, the

The reader witnesses a robbery and knows who took the jewels. And the thief is a perfect gentleman and you can't help loving him. The detective in this story was realistic and he made mistakes.Everyone is wearing scads of jewels - emeralds, diamonds, pearls - and there's a thief using the fog as a cover to score big, big, big. What's a girl to do if she thinks she recognizes the thief's voice? When it's attached to a very attractive young man? Jolly good fun!