Letter to Houdini (20 june 1922)
From The Arthur Conan Doyle Encyclopedia
June 20th, 1922.
... No, the Powell explanation, won't do. Not only is he the one man who would wish to get me, but in the evening, Mrs. M., the lady medium, got, "there is a man here. He wants to say that he is sorry he had to speak so abruptly this afternoon." The message was then broken by your Mother's renewed message and !o we got no name. But it confirms me in the belief that it was Powell. However, you will no doubt test your powers further.
A. Conan Doyle.