1894, Arthur Conan Doyle, The Parasite Chapter I, I like none of these mystery-mongers, but the amateur least of all. With the paid performer you may pounce upon him and expose him the instant that you have seen through his trick.
1916, William Le Queux, The Place of Dragons, "Curious affair, isn't it?" "Very." "Now, you're a bit of a mystery-monger, Vidal. What's your theory—eh?"
1925, A. B. Walkley, Pirandello, the Mystery-Monger, But I began by calling him a mystery-monger, and it is perhaps time I made good. What I mean is this. Not content with serving up to you philosophic or psychological theories and using them, dramatically, for what they will carry, Pirandello frequently uses them for more than they will carry, and, as I think, deliberately mystifies you, for the sake of “getting away with it†in the confusion.