The letter bore the Colchester post-mark, and she, I knew, lived at Melbourne House in that town.
"I suppose you will get into communication with her," I exclaimed presently.
"Of course. Any line of action in the elucidation of the mystery is worth trying. But what I cannot quite understand is, why she requires blood-money," remarked the detective as we strolled together in the arcaded entrance to the Underground Station at High Street, Kensington. "I always look askance at such 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."