letters. We receive many of them at the
Yard. Not a single murder mystery comes before us, but we receive letters
from cranks and others offering to point out the guilty person."

"But may not the writers of such letters be endeavouring to fasten guilt
upon perfectly innocent persons against whom they have spite?" I
suggested.

"Ah! That's just it, Mr. Royle," exclaimed my companion gravely. "Yet it
is so terribly difficult to discriminate, and I fear we often, in our
hesitation, place aside letters, the writers of which could really give
valuable information."

"But in this case, what are your natural inclinations?" I asked. "I know
that you possess a curious, almost unique, intuition as to what is fact
and what is fiction. What is, may I term it, your private opinion?"

He halted against the long shop-windows of Derry & Toms, and paused for
several minutes.

"Well," he said at last in a deeply earnest tone, "I tell you frankly,
Mr. Royle, what I believe. First, I don't think that the man Kemsley,
although an impostor, was the actual assassin."

"Why?" I gasped.

"Well--I've very carefully studied the whole problem. I've looked at it
from every point of view," he said. "I confess the one fact puzzles me,
that this man Kemsley could live so long in London and pose as the dead
Sir Digby if he were not the actual man himself, has amazed me! In his
position as Sir Digby, the great engineer, he must have met in society
many persons who knew him. We have evidence that he constantly moved in
the best circles in Mayfair, and apparently without the slightest
compunction. Yet, in contradiction, we have the remarkable fact that the
real Sir Digby died in South America in very mysterious and tragic
circumstances."

I saw that a problem was presented to Inspector Edwards which sorely
puzzled him, as it certainly did myself.

"Well," I asked after a pause, and then with some trepidation put the
question, "what do you intend doing?"

"Doing!" he echoed. "There is but one course to pursue. We must get in
touch with this woman who says she knows the truth, and obtain what
information we can from her. Perhaps she can reveal the identity of the
woman whose fingers touched that glass-topped table in the room where
the crime was committed. If so, that will tell us a great deal, Mr.
Royle." Then, taking a cigarette from his pocket and tapping it, he
added, "Do you know, I've been wondering of late how it is that you got
those f